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//---------------------------------------------------------------------
// <copyright file="PreProcessor.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//
// @owner Microsoft
// @backupOwner Microsoft
//---------------------------------------------------------------------
//using System.Diagnostics; // Please use PlanCompiler.Assert instead of Debug.Assert in this class...
// It is fine to use Debug.Assert in cases where you assert an obvious thing that is supposed
// to prevent from simple mistakes during development (e.g. method argument validation
// in cases where it was you who created the variables or the variables had already been validated or
// in "else" clauses where due to code changes (e.g. adding a new value to an enum type) the default
// "else" block is chosen why the new condition should be treated separately). This kind of asserts are
// (can be) helpful when developing new code to avoid simple mistakes but have no or little value in
// the shipped product.
// PlanCompiler.Assert *MUST* be used to verify conditions in the trees. These would be assumptions
// about how the tree was built etc. - in these cases we probably want to throw an exception (this is
// what PlanCompiler.Assert does when the condition is not met) if either the assumption is not correct
// or the tree was built/rewritten not the way we thought it was.
// Use your judgment - if you rather remove an assert than ship it use Debug.Assert otherwise use
// PlanCompiler.Assert.
//
// The PreProcessor module is responsible for performing any required preprocessing
// on the tree and gathering information before subsequent phases may be performed.
// The main responsibilites of the preprocessor are:
//
// (a) gathering information about all structured types and entitysets referenced in the
// query
// (b) expanding views, navigate operators, and rewritting other type related operators
// (c) gathering information about which subsequent phases may be requried
// (d) pulling sort over project, and removing unnecessary sorts
// (e) eliminates certain operations by translating them into equivalent subtrees
// (ElementOp, NewMultisetOp)
//
namespace System.Data.Query.PlanCompiler
{
using System.Collections.Generic;
using System.Data.Common;
using System.Data.Common.Utils;
using System.Data.Entity;
using System.Data.Mapping;
using System.Data.Metadata.Edm;
using System.Data.Query.InternalTrees;
internal class DiscriminatorMapInfo
{
internal EntityTypeBase RootEntityType;
internal bool IncludesSubTypes;
internal ExplicitDiscriminatorMap DiscriminatorMap;
internal DiscriminatorMapInfo(EntityTypeBase rootEntityType, bool includesSubTypes, ExplicitDiscriminatorMap discriminatorMap)
{
RootEntityType = rootEntityType;
IncludesSubTypes = includesSubTypes;
DiscriminatorMap = discriminatorMap;
}
/// <summary>
/// Merge the discriminatorMap info we just found with what we've already found.
///
/// In practice, if either the current or the new map is from an OfTypeOnly view, we
/// have to avoid the optimizations.
///
/// If we have a new map that is a superset of the current map, then we can just swap
/// the new map for the current one.
///
/// If the current map is tha super set of the new one ther's nothing to do.
///
/// (Of course, if neither has changed, then we really don't need to look)
/// </summary>
internal void Merge(EntityTypeBase neededRootEntityType, bool includesSubtypes, ExplicitDiscriminatorMap discriminatorMap)
{
// If what we've found doesn't exactly match what we are looking for we have more work to do
if (RootEntityType != neededRootEntityType || IncludesSubTypes != includesSubtypes)
{
if (!IncludesSubTypes || !includesSubtypes)
{
// If either the original or the new map is from an of-type-only view we can't
// merge, we just have to not optimize this case.
DiscriminatorMap = null;
}
if (TypeSemantics.IsSubTypeOf(RootEntityType, neededRootEntityType))
{
// we're asking for a super type of existing type, and what we had is a proper
// subset of it -we can replace the existing item.
RootEntityType = neededRootEntityType;
DiscriminatorMap = discriminatorMap;
}
if (!TypeSemantics.IsSubTypeOf(neededRootEntityType, RootEntityType))
{
// If either the original or the new map is from an of-type-only view we can't
// merge, we just have to not optimize this case.
DiscriminatorMap = null;
}
}
}
}
/// <summary>
/// The PreProcessor module is responsible for performing any required preprocessing
/// on the tree and gathering information before subsequent phases may be performed.
/// </summary>
internal class PreProcessor : SubqueryTrackingVisitor
{
#region private state
/// <summary>
/// Tracks affinity of entity constructors to entity sets (aka scoped entity type constructors).
/// Scan view ops and entityset-bound tvfs push corresponding entity sets so that their child nodes representing entity constructors could
/// determine the entity set to which the constructed entity belongs.
/// </summary>
private readonly Stack<EntitySet> m_entityTypeScopes = new Stack<EntitySet>();
// Track referenced types, entitysets, entitycontainers, free floating entity constructor types
// and types needing a null sentinel.
private readonly HashSet<EntityContainer> m_referencedEntityContainers = new HashSet<EntityContainer>();
private readonly HashSet<EntitySet> m_referencedEntitySets = new HashSet<EntitySet>();
private readonly HashSet<TypeUsage> m_referencedTypes = new HashSet<TypeUsage>();
private readonly HashSet<EntityType> m_freeFloatingEntityConstructorTypes = new HashSet<EntityType>();
private readonly HashSet<string> m_typesNeedingNullSentinel = new HashSet<string>();
private readonly Dictionary<EdmFunction, EdmProperty[]> m_tvfResultKeys = new Dictionary<EdmFunction, EdmProperty[]>();
/// <summary>
/// Helper for rel properties
/// </summary>
private RelPropertyHelper m_relPropertyHelper;
// Track discriminator metadata.
private bool m_suppressDiscriminatorMaps;
private readonly Dictionary<EntitySetBase, DiscriminatorMapInfo> m_discriminatorMaps = new Dictionary<EntitySetBase, DiscriminatorMapInfo>();
#endregion
#region constructors
private PreProcessor(PlanCompiler planCompilerState)
: base(planCompilerState)
{
m_relPropertyHelper = new RelPropertyHelper(m_command.MetadataWorkspace, m_command.ReferencedRelProperties);
}
#endregion
#region public methods
/// <summary>
/// The driver routine.
/// </summary>
/// <param name="planCompilerState">plan compiler state</param>
/// <param name="typeInfo">type information about all types/sets referenced in the query</param>
/// <param name="tvfResultKeys">inferred key columns of tvfs return types</param>
internal static void Process(
PlanCompiler planCompilerState,
out StructuredTypeInfo typeInfo,
out Dictionary<EdmFunction, EdmProperty[]> tvfResultKeys)
{
PreProcessor preProcessor = new PreProcessor(planCompilerState);
preProcessor.Process(out tvfResultKeys);
StructuredTypeInfo.Process(planCompilerState.Command,
preProcessor.m_referencedTypes,
preProcessor.m_referencedEntitySets,
preProcessor.m_freeFloatingEntityConstructorTypes,
preProcessor.m_suppressDiscriminatorMaps ? null : preProcessor.m_discriminatorMaps,
preProcessor.m_relPropertyHelper,
preProcessor.m_typesNeedingNullSentinel,
out typeInfo);
}
#endregion
#region private methods
#region driver
internal void Process(out Dictionary<EdmFunction, EdmProperty[]> tvfResultKeys)
{
m_command.Root = VisitNode(m_command.Root);
//
// Add any Vars that are of structured type - if the Vars aren't
// referenced via a VarRefOp, we end up losing them...
//
foreach (Var v in m_command.Vars)
{
AddTypeReference(v.Type);
}
//
// If we have any "structured" types, then we need to run through NTE
//
if (m_referencedTypes.Count > 0)
{
m_compilerState.MarkPhaseAsNeeded(PlanCompilerPhase.NTE);
//
// Find any structured types that are projected at the top level, and
// ensure that we can handle their nullability.
//
PhysicalProjectOp ppOp = (PhysicalProjectOp)m_command.Root.Op; // this better be the case or we have other problems.
ppOp.ColumnMap.Accept(StructuredTypeNullabilityAnalyzer.Instance, m_typesNeedingNullSentinel);
}
tvfResultKeys = m_tvfResultKeys;
}
#endregion
#region private state maintenance - type and set information
/// <summary>
/// Mark this EntitySet as referenced in the query
/// </summary>
/// <param name="entitySet"></param>
private void AddEntitySetReference(EntitySet entitySet)
{
m_referencedEntitySets.Add(entitySet);
if (!m_referencedEntityContainers.Contains(entitySet.EntityContainer))
{
m_referencedEntityContainers.Add(entitySet.EntityContainer);
}
}
/// <summary>
/// Mark this type as being referenced in the query, if it is a structured, collection or enum type.
/// </summary>
/// <param name="type">type to reference</param>
private void AddTypeReference(TypeUsage type)
{
if (TypeUtils.IsStructuredType(type) || TypeUtils.IsCollectionType(type) || TypeUtils.IsEnumerationType(type))
{
m_referencedTypes.Add(type);
}
}
/// <summary>
/// Get the list of relationshipsets that can hold instances of the given relationshiptype
///
/// We identify the list of relationshipsets in the current list of entitycontainers that are
/// of the given type. Since we don't yet support relationshiptype subtyping, this is a little
/// easier than the entity version
/// </summary>
/// <param name="relType">the relationship type to look for</param>
/// <returns>the list of relevant relationshipsets</returns>
private List<RelationshipSet> GetRelationshipSets(RelationshipType relType)
{
List<RelationshipSet> relSets = new List<RelationshipSet>();
foreach (EntityContainer entityContainer in m_referencedEntityContainers)
{
foreach (EntitySetBase set in entityContainer.BaseEntitySets)
{
RelationshipSet relSet = set as RelationshipSet;
if (relSet != null &&
relSet.ElementType.Equals(relType))
{
relSets.Add(relSet);
}
}
}
return relSets;
}
/// <summary>
/// Find all entitysets (that are reachable in the current query) that can hold instances that
/// are *at least* of type "entityType".
/// An entityset ES of type T1 can hold instances that are at least of type T2, if one of the following
/// is true
/// - T1 is a subtype of T2
/// - T2 is a subtype of T1
/// - T1 is equal to T2
/// </summary>
/// <param name="entityType">the desired entity type</param>
/// <returns>list of all entitysets of the desired shape</returns>
private List<EntitySet> GetEntitySets(TypeUsage entityType)
{
List<EntitySet> sets = new List<EntitySet>();
foreach (EntityContainer container in m_referencedEntityContainers)
{
foreach (EntitySetBase baseSet in container.BaseEntitySets)
{
EntitySet set = baseSet as EntitySet;
if (set != null &&
(set.ElementType.Equals(entityType.EdmType) ||
TypeSemantics.IsSubTypeOf(entityType.EdmType, set.ElementType) ||
TypeSemantics.IsSubTypeOf(set.ElementType, entityType.EdmType)))
{
sets.Add(set);
}
}
}
return sets;
}
#endregion
#region View Expansion
/// <summary>
/// Gets the "expanded" query mapping view for the specified C-Space entity set
/// </summary>
/// <param name="node">The current node</param>
/// <param name="scanTableOp">The scanTableOp that references the entity set</param>
/// <param name="typeFilter">
/// An optional type filter to apply to the generated view.
/// Set to <c>null</c> on return if the generated view renders the type filter superfluous.
/// </param>
/// <returns>A node that is the root of the new expanded view</returns>
private Node ExpandView(Node node, ScanTableOp scanTableOp, ref IsOfOp typeFilter)
{
EntitySetBase entitySet = scanTableOp.Table.TableMetadata.Extent;
PlanCompiler.Assert(entitySet != null, "The target of a ScanTableOp must reference an EntitySet to be used with ExpandView");
PlanCompiler.Assert(entitySet.EntityContainer.DataSpace == DataSpace.CSpace, "Store entity sets cannot have Query Mapping Views and should not be used with ExpandView");
if (typeFilter != null &&
!typeFilter.IsOfOnly &&
TypeSemantics.IsSubTypeOf(entitySet.ElementType, typeFilter.IsOfType.EdmType))
{
//
// If a type filter is being applied to the ScanTableOp, but that filter is asking
// for all elements that are the same type or a supertype of the element type of the
// target entity set, then the type filter is a no-op and can safely be discarded -
// IF AND ONLY IF the type filter is 'OfType' - which includes subtypes - and NOT
// 'IsOfOnly' - which requires an exact type match, and so does not include subtypes.
//
typeFilter = null;
}
//
// Call the GetGeneratedView method to retrieve the query mapping view for the extent referenced
// by the ScanTableOp. The actual method used to do this differs depending on whether the default
// Query Mapping View is sufficient or a targeted view that only filters by element type is required.
//
System.Data.Mapping.ViewGeneration.GeneratedView definingQuery = null;
EntityTypeBase requiredType = scanTableOp.Table.TableMetadata.Extent.ElementType;
bool includeSubtypes = true;
if (typeFilter != null)
{
//
// A type filter is being applied to the ScanTableOp; it may be possible to produce
// an optimized expansion of the view based on type-specific views generated for the
// C-Space entity set.
// The type for which the view should be tuned is the 'OfType' specified on the type filter.
// If the type filter is an 'IsOfOnly' filter then the view should NOT include subtypes of the required type.
//
requiredType = (EntityTypeBase)typeFilter.IsOfType.EdmType;
includeSubtypes = !typeFilter.IsOfOnly;
if (m_command.MetadataWorkspace.TryGetGeneratedViewOfType(entitySet, requiredType, includeSubtypes, out definingQuery))
{
//
// At this point a type-specific view was found that satisifies the type filter's
// constraints in terms of required type and whether subtypes should be included;
// the type filter itself is now unnecessary and should be set to null indicating
// that it can be safely removed (see ProcessScanTableOp and Visit(FilterOp) for this).
//
typeFilter = null;
}
}
//
// If a generated view has not been obtained at this point then either:
// - A type filter was specified but no type-specific view exists that satisfies its constraints.
// OR
// - No type filter was specified.
// In either case the default query mapping view for the referenced entity set should now be retrieved.
//
if (null == definingQuery)
{
definingQuery = m_command.MetadataWorkspace.GetGeneratedView(entitySet);
}
//
// If even the default query mapping view was not found then we cannot continue.
// This implies that the set was not mapped, which should not be allowed, therefore
// a retail assert is used here instead of a regular exception.
//
PlanCompiler.Assert(definingQuery != null, Strings.ADP_NoQueryMappingView(entitySet.EntityContainer.Name, entitySet.Name));
//
// At this point we're guaranteed to have found a defining query for the view.
// We're now going to convert this into an IQT, and then copy it into our own IQT.
//
Node ret = definingQuery.GetInternalTree(m_command);
//
// Make sure we're tracking what we've asked any discriminator maps to contain.
//
DetermineDiscriminatorMapUsage(ret, entitySet, requiredType, includeSubtypes);
//
// Build up a ScanViewOp to "cap" the defining query below
//
ScanViewOp scanViewOp = m_command.CreateScanViewOp(scanTableOp.Table);
ret = m_command.CreateNode(scanViewOp, ret);
return ret;
}
/// <summary>
/// If the discrminator map we're already tracking for this type (in this entityset)
/// isn't already rooted at our required type, then we have to suppress the use of
/// the descriminator maps when we constrct the structuredtypes; see SQLBUDT #615744
/// </summary>
private void DetermineDiscriminatorMapUsage(Node viewNode, EntitySetBase entitySet, EntityTypeBase rootEntityType, bool includeSubtypes)
{
ExplicitDiscriminatorMap discriminatorMap = null;
// we expect the view to be capped with a project; we're just being careful here.
if (viewNode.Op.OpType == OpType.Project)
{
DiscriminatedNewEntityOp discriminatedNewEntityOp = viewNode.Child1.Child0.Child0.Op as DiscriminatedNewEntityOp;
if (null != discriminatedNewEntityOp)
{
discriminatorMap = discriminatedNewEntityOp.DiscriminatorMap;
}
}
DiscriminatorMapInfo discriminatorMapInfo;
if (!m_discriminatorMaps.TryGetValue(entitySet, out discriminatorMapInfo))
{
if (null == rootEntityType)
{
rootEntityType = entitySet.ElementType;
includeSubtypes = true;
}
discriminatorMapInfo = new DiscriminatorMapInfo(rootEntityType, includeSubtypes, discriminatorMap);
m_discriminatorMaps.Add(entitySet, discriminatorMapInfo);
}
else
{
discriminatorMapInfo.Merge(rootEntityType, includeSubtypes, discriminatorMap);
}
}
#endregion
#region NavigateOp rewrites
/// <summary>
/// Rewrites a NavigateOp tree in the following fashion
/// SELECT VALUE r.ToEnd
/// FROM (SELECT VALUE r1 FROM RS1 as r1
/// UNION ALL
/// SELECT VALUE r2 FROM RS2 as r2
/// ...
/// SELECT VALUE rN FROM RSN as rN) as r
/// WHERE r.FromEnd = sourceRef
///
/// RS1, RS2 etc. are the set of all relationshipsets that can hold instances of the specified
/// relationship type. "sourceRef" is the single (ref-type) argument to the NavigateOp that
/// represents the from-end of the navigation traversal
/// If the toEnd is multi-valued, then we stick a Collect(PhysicalProject( over the subquery above
///
/// A couple of special cases.
/// If no relationship sets can be found, we return a NULL (if the
/// toEnd is single-valued), or an empty multiset (if the toEnd is multi-valued)
///
/// If the toEnd is single-valued, *AND* the input Op is a GetEntityRefOp, then
/// we convert the NavigateOp into a RelPropertyOp over the entity.
/// </summary>
/// <param name="navigateOpNode">the navigateOp tree</param>
/// <param name="navigateOp">the navigateOp</param>
/// <param name="outputVar">the output var produced by the subquery (ONLY if the to-End is single-valued)</param>
/// <returns>the resulting node</returns>
private Node RewriteNavigateOp(Node navigateOpNode, NavigateOp navigateOp, out Var outputVar)
{
outputVar = null;
//
// Currently, navigation of composition relationships is not supported.
//
if (!Helper.IsAssociationType(navigateOp.Relationship))
{
throw EntityUtil.NotSupported(System.Data.Entity.Strings.Cqt_RelNav_NoCompositions);
}
//
// If the input to the navigateOp is a GetEntityRefOp, and the navigation
// is to the 1-end of the relationship, convert this into a RelPropertyOp instead - operating on the
// input child to the GetEntityRefOp
//
if (navigateOpNode.Child0.Op.OpType == OpType.GetEntityRef &&
(navigateOp.ToEnd.RelationshipMultiplicity == RelationshipMultiplicity.ZeroOrOne ||
navigateOp.ToEnd.RelationshipMultiplicity == RelationshipMultiplicity.One))
{
PlanCompiler.Assert(m_command.IsRelPropertyReferenced(navigateOp.RelProperty),
"Unreferenced rel property? " + navigateOp.RelProperty);
Op relPropertyOp = m_command.CreateRelPropertyOp(navigateOp.RelProperty);
Node relPropertyNode = m_command.CreateNode(relPropertyOp,
navigateOpNode.Child0.Child0);
return relPropertyNode;
}
List<RelationshipSet> relationshipSets = GetRelationshipSets(navigateOp.Relationship);
//
// Special case: when no relationshipsets can be found. Return NULL or an empty multiset,
// depending on the multiplicity of the toEnd
//
if (relationshipSets.Count == 0)
{
//
// If we're navigating to the 1-end of the relationship, then simply return a null constant
//
if (navigateOp.ToEnd.RelationshipMultiplicity != RelationshipMultiplicity.Many)
{
return m_command.CreateNode(m_command.CreateNullOp(navigateOp.Type));
}
else // return an empty set
{
return m_command.CreateNode(m_command.CreateNewMultisetOp(navigateOp.Type));
}
}
//
// Build up a UNION-ALL ladder over all the relationshipsets
//
List<Node> scanTableNodes = new List<Node>();
List<Var> scanTableVars = new List<Var>();
foreach (RelationshipSet relSet in relationshipSets)
{
TableMD tableMD = Command.CreateTableDefinition(relSet);
ScanTableOp tableOp = m_command.CreateScanTableOp(tableMD);
Node branchNode = m_command.CreateNode(tableOp);
Var branchVar = tableOp.Table.Columns[0];
scanTableVars.Add(branchVar);
scanTableNodes.Add(branchNode);
}
Node unionAllNode = null;
Var unionAllVar;
m_command.BuildUnionAllLadder(scanTableNodes, scanTableVars, out unionAllNode, out unionAllVar);
//
// Now build up the predicate
//
Node targetEnd = m_command.CreateNode(m_command.CreatePropertyOp(navigateOp.ToEnd),
m_command.CreateNode(m_command.CreateVarRefOp(unionAllVar)));
Node sourceEnd = m_command.CreateNode(m_command.CreatePropertyOp(navigateOp.FromEnd),
m_command.CreateNode(m_command.CreateVarRefOp(unionAllVar)));
Node predicateNode = m_command.BuildComparison(OpType.EQ, navigateOpNode.Child0, sourceEnd);
Node filterNode = m_command.CreateNode(m_command.CreateFilterOp(),
unionAllNode, predicateNode);
Var projectVar;
Node projectNode = m_command.BuildProject(filterNode, targetEnd, out projectVar);
//
// Finally, some magic about single-valued vs collection-valued ends
//
Node ret;
if (navigateOp.ToEnd.RelationshipMultiplicity == RelationshipMultiplicity.Many)
{
ret = m_command.BuildCollect(projectNode, projectVar);
}
else
{
ret = projectNode;
outputVar = projectVar;
}
return ret;
}
#endregion
#region DerefOp Rewrites
/// <summary>
/// Build up a node tree that represents the set of instances from the given table that are at least
/// of the specified type ("ofType"). If "ofType" is NULL, then all rows are returned
///
/// Return the outputVar from the nodetree
/// </summary>
/// <param name="entitySet">the entityset or relationshipset to scan over</param>
/// <param name="ofType">the element types we're interested in</param>
/// <param name="resultVar">the output var produced by this node tree</param>
/// <returns>the node tree</returns>
private Node BuildOfTypeTable(EntitySetBase entitySet, TypeUsage ofType, out Var resultVar)
{
TableMD tableMetadata = Command.CreateTableDefinition(entitySet);
ScanTableOp tableOp = m_command.CreateScanTableOp(tableMetadata);
Node tableNode = m_command.CreateNode(tableOp);
Var tableVar = tableOp.Table.Columns[0];
Node resultNode;
//
// Build a logical "oftype" expression - simply a filter predicate
//
if ((ofType != null) && !entitySet.ElementType.EdmEquals(ofType.EdmType))
{
m_command.BuildOfTypeTree(tableNode, tableVar, ofType, true, out resultNode, out resultVar);
}
else
{
resultNode = tableNode;
resultVar = tableVar;
}
return resultNode;
}
/// <summary>
/// Produces a relop tree that "logically" produces the target of the derefop. In essence, this gets rewritten
/// into
/// SELECT VALUE e
/// FROM (SELECT VALUE e0 FROM OFTYPE(ES0, T) as e0
/// UNION ALL
/// SELECT VALUE e1 FROM OFTYPE(ES1, T) as e1
/// ...
/// SELECT VALUE eN from OFTYPE(ESN, T) as eN)) as e
/// WHERE REF(e) = myRef
///
/// "T" is the target type of the Deref, and myRef is the (single) argument to the DerefOp
///
/// ES0, ES1 etc. are all the EntitySets that could hold instances that are at least of type "T". We identify this list of sets
/// by looking at all entitycontainers referenced in the query, and looking at all entitysets in those
/// containers that are of the right type
/// An EntitySet ES (of entity type X) can hold instances of T, if one of the following is true
/// - T is a subtype of X
/// - X is equal to T
/// Our situation is a little trickier, since we also need to look for cases where X is a subtype of T.
/// </summary>
/// <param name="derefOpNode">the derefOp subtree</param>
/// <param name="derefOp">the derefOp</param>
/// <param name="outputVar">output var produced</param>
/// <returns>the subquery described above</returns>
private Node RewriteDerefOp(Node derefOpNode, DerefOp derefOp, out Var outputVar)
{
TypeUsage entityType = derefOp.Type;
List<EntitySet> targetEntitySets = GetEntitySets(entityType);
if (targetEntitySets.Count == 0)
{
// We didn't find any entityset that could match this. Simply return a null-value
outputVar = null;
return m_command.CreateNode(m_command.CreateNullOp(entityType));
}
List<Node> scanTableNodes = new List<Node>();
List<Var> scanTableVars = new List<Var>();
foreach (EntitySet entitySet in targetEntitySets)
{
Var tableVar;
Node tableNode = BuildOfTypeTable(entitySet, entityType, out tableVar);
scanTableNodes.Add(tableNode);
scanTableVars.Add(tableVar);
}
Node unionAllNode;
Var unionAllVar;
m_command.BuildUnionAllLadder(scanTableNodes, scanTableVars, out unionAllNode, out unionAllVar);
//
// Finally build up the key comparison predicate
//
Node entityRefNode = m_command.CreateNode(
m_command.CreateGetEntityRefOp(derefOpNode.Child0.Op.Type),
m_command.CreateNode(m_command.CreateVarRefOp(unionAllVar)));
Node keyComparisonPred = m_command.BuildComparison(OpType.EQ, derefOpNode.Child0, entityRefNode);
Node filterNode = m_command.CreateNode(
m_command.CreateFilterOp(),
unionAllNode,
keyComparisonPred);
outputVar = unionAllVar;
return filterNode;
}
#endregion
#region NavigationProperty Rewrites
/// <summary>
/// Find the entityset that corresponds to the specified end of the relationship.
///
/// We must find one - else we assert.
/// </summary>
/// <param name="relationshipSet">the relationshipset</param>
/// <param name="targetEnd">the destination end of the relationship traversal</param>
/// <returns>the entityset corresponding to the target end</returns>
private static EntitySetBase FindTargetEntitySet(RelationshipSet relationshipSet, RelationshipEndMember targetEnd)
{
EntitySetBase entitySet = null;
AssociationSet associationSet = (AssociationSet)relationshipSet;
// find the corresponding entityset
entitySet = null;
foreach (AssociationSetEnd e in associationSet.AssociationSetEnds)
{
if (e.CorrespondingAssociationEndMember.EdmEquals(targetEnd))
{
entitySet = e.EntitySet;
break;
}
}
PlanCompiler.Assert(entitySet != null, "Could not find entityset for relationshipset " + relationshipSet + ";association end " + targetEnd);
return entitySet;
}
/// <summary>
/// Builds up a join between the relationshipset and the entityset corresponding to its toEnd. In essence,
/// we produce
/// SELECT r, e
/// FROM RS as r, OFTYPE(ES, T) as e
/// WHERE r.ToEnd = Ref(e)
///
/// "T" is the entity type of the toEnd of the relationship.
/// </summary>
/// <param name="relSet">the relationshipset</param>
/// <param name="end">the toEnd of the relationship</param>
/// <param name="rsVar">the var representing the relationship instance ("r") in the output subquery</param>
/// <param name="esVar">the var representing the entity instance ("e") in the output subquery</param>
/// <returns>the join subquery described above</returns>
private Node BuildJoinForNavProperty(RelationshipSet relSet, RelationshipEndMember end,
out Var rsVar, out Var esVar)
{
EntitySetBase entitySet = FindTargetEntitySet(relSet, end);
//
// Build out the ScanTable ops for the relationshipset and the entityset. Add the
//
Node asTableNode = BuildOfTypeTable(relSet, null, out rsVar);
Node esTableNode = BuildOfTypeTable(entitySet, TypeHelpers.GetElementTypeUsage(end.TypeUsage), out esVar);
//
// Build up a join between the entityset and the associationset; join on the to-end
//
Node joinPredicate = m_command.BuildComparison(OpType.EQ,
m_command.CreateNode(m_command.CreateGetEntityRefOp(end.TypeUsage), m_command.CreateNode(m_command.CreateVarRefOp(esVar))),
m_command.CreateNode(m_command.CreatePropertyOp(end), m_command.CreateNode(m_command.CreateVarRefOp(rsVar)))
);
Node joinNode = m_command.CreateNode(m_command.CreateInnerJoinOp(),
asTableNode, esTableNode, joinPredicate);
return joinNode;
}
/// <summary>
/// Rewrite a navigation property when the target end has multiplicity
/// of one (or zero..one) and the source end has multiplicity of many.
///
/// Note that this translation is also valid for a navigation property when the target
/// end has multiplicity of one (or zero..one) and the source end has multiplicity of one
/// (or zero..one), but a different translation is used because it yields a simpler query in some cases.
///
/// We simply pick up the corresponding rel property from the input entity, and
/// apply a deref operation
/// NavProperty(e, n) => deref(relproperty(e, r))
/// where e is the entity expression, n is the nav-property, and r is the corresponding
/// rel-property
/// </summary>
/// <param name="relProperty">the rel-property describing the navigation</param>
/// <param name="sourceEntityNode">entity instance that we're starting the traversal from</param>
/// <param name="resultType">type of the target entity</param>
/// <returns>a rewritten subtree</returns>
private Node RewriteManyToOneNavigationProperty(RelProperty relProperty,
Node sourceEntityNode, TypeUsage resultType)
{
RelPropertyOp relPropertyOp = m_command.CreateRelPropertyOp(relProperty);
Node relPropertyNode = m_command.CreateNode(relPropertyOp, sourceEntityNode);
DerefOp derefOp = m_command.CreateDerefOp(resultType);
Node derefNode = m_command.CreateNode(derefOp, relPropertyNode);
return derefNode;
}
/// <summary>
/// Rewrite a navigation property when the source end has multiplicity
/// of one (or zero..one) and the target end has multiplicity of many.
///
/// <see cref="RewriteFromOneNavigationProperty"/>
/// We also build out a CollectOp over the subquery above, and return that
/// </summary>
/// <param name="relProperty">the rel-property describing the relationship traversal</param>
/// <param name="relationshipSets">the list of relevant relationshipsets</param>
/// <param name="sourceRefNode">node tree corresponding to the source entity ref</param>
/// <returns>the rewritten subtree</returns>
private Node RewriteOneToManyNavigationProperty(RelProperty relProperty,
List<RelationshipSet> relationshipSets,
Node sourceRefNode)
{
Var outputVar;
Node ret = RewriteFromOneNavigationProperty(relProperty, relationshipSets, sourceRefNode, out outputVar);
// The return value is a collection, but used as a property, thus it needs to be capped with a collect
ret = m_command.BuildCollect(ret, outputVar);
return ret;
}
/// <summary>
/// Rewrite a navigation property when the target end has multiplicity
/// of one (or zero..one) and the source end has multiplicity of one (or zero..one).
///
/// <see cref="RewriteFromOneNavigationProperty"/>
/// We add the translation as a subquery to the parent rel op and return a reference to
/// the corresponding var
/// </summary>
/// <param name="relProperty">the rel-property describing the relationship traversal</param>
/// <param name="relationshipSets">the list of relevant relationshipsets</param>
/// <param name="sourceRefNode">node tree corresponding to the source entity ref</param>
/// <returns>the rewritten subtree</returns>
private Node RewriteOneToOneNavigationProperty(RelProperty relProperty,
List<RelationshipSet> relationshipSets,
Node sourceRefNode)
{
Var outputVar;
Node ret = RewriteFromOneNavigationProperty(relProperty, relationshipSets, sourceRefNode, out outputVar);
ret = VisitNode(ret);
ret = AddSubqueryToParentRelOp(outputVar, ret);
return ret;
}
/// <summary>
/// Translation for Navigation Properties with a 0 or 0..1 source end
/// In essence, we find all the relevant target entitysets, and then compare the
/// rel-property on the target end with the source ref
///
/// Converts
/// NavigationProperty(e, r)
/// into
/// SELECT VALUE t
/// FROM (SELECT VALUE e1 FROM ES1 as e1
/// UNION ALL
/// SELECT VALUE e2 FROM ES2 as e2
/// UNION ALL
/// ...
/// ) as t
/// WHERE RelProperty(t, r') = GetEntityRef(e)
///
/// r' is the inverse-relproperty for r
/// </summary>
/// <param name="relProperty">the rel-property describing the relationship traversal</param>
/// <param name="relationshipSets">the list of relevant relationshipsets</param>
/// <param name="sourceRefNode">node tree corresponding to the source entity ref</param>
/// <param name="outputVar">the var representing the output</param>
/// <returns>the rewritten subtree</returns>
private Node RewriteFromOneNavigationProperty(RelProperty relProperty, List<RelationshipSet> relationshipSets, Node sourceRefNode, out Var outputVar)
{
PlanCompiler.Assert(relationshipSets.Count > 0, "expected at least one relationshipset here");
PlanCompiler.Assert(relProperty.FromEnd.RelationshipMultiplicity != RelationshipMultiplicity.Many,
"Expected source end multiplicity to be one. Found 'Many' instead " + relProperty);
TypeUsage entityType = TypeHelpers.GetElementTypeUsage(relProperty.ToEnd.TypeUsage);
List<Node> scanTableNodes = new List<Node>(relationshipSets.Count);
List<Var> scanTableVars = new List<Var>(relationshipSets.Count);
foreach (RelationshipSet r in relationshipSets)
{
EntitySetBase entitySet = FindTargetEntitySet(r, relProperty.ToEnd);
Var tableVar;
Node tableNode = BuildOfTypeTable(entitySet, entityType, out tableVar);
scanTableNodes.Add(tableNode);
scanTableVars.Add(tableVar);
}
//
// Build the union-all node
//
Node unionAllNode;
m_command.BuildUnionAllLadder(scanTableNodes, scanTableVars, out unionAllNode, out outputVar);
//
// Now build up the appropriate filter. Select out the relproperty from the other end
//
RelProperty inverseRelProperty = new RelProperty(relProperty.Relationship, relProperty.ToEnd, relProperty.FromEnd);
PlanCompiler.Assert(m_command.IsRelPropertyReferenced(inverseRelProperty),
"Unreferenced rel property? " + inverseRelProperty);
Node inverseRelPropertyNode = m_command.CreateNode(
m_command.CreateRelPropertyOp(inverseRelProperty),
m_command.CreateNode(m_command.CreateVarRefOp(outputVar)));
Node predicateNode = m_command.BuildComparison(OpType.EQ,
sourceRefNode, inverseRelPropertyNode);
Node ret = m_command.CreateNode(m_command.CreateFilterOp(), unionAllNode, predicateNode);
return ret;
}
/// <summary>
/// Rewrite a navigation property when the target end has multiplicity
/// many and the source end has multiplicity of many.
///
/// Consider this a rewrite of DEREF(NAVIGATE(r)) where "r" is a many-to-many relationship
///
/// We essentially produce the following subquery
/// SELECT VALUE x.e
/// FROM (SELECT r1 as r, e1 as e FROM RS1 as r1 INNER JOIN OFTYPE(ES1, T) as e1 on r1.ToEnd = Ref(e1)
/// UNION ALL
/// SELECT r1 as r, e1 as e FROM RS1 as r1 INNER JOIN OFTYPE(ES1, T) as e1 on r1.ToEnd = Ref(e1)
/// ...
/// ) as x
/// WHERE x.r.FromEnd = sourceRef
///
/// RS1, RS2 etc. are the relevant relationshipsets
/// ES1, ES2 etc. are the corresponding entitysets for the toEnd of the relationship
/// sourceRef is the ref argument
/// T is the type of the target-end of the relationship
///
/// We then build a CollectOp over the subquery above
/// </summary>
/// <param name="relProperty">the rel property to traverse</param>
/// <param name="relationshipSets">list of relevant relationshipsets</param>
/// <param name="sourceRefNode">source ref</param>
/// <returns></returns>
private Node RewriteManyToManyNavigationProperty(RelProperty relProperty,
List<RelationshipSet> relationshipSets,
Node sourceRefNode)
{
PlanCompiler.Assert(relationshipSets.Count > 0, "expected at least one relationshipset here");
PlanCompiler.Assert(relProperty.ToEnd.RelationshipMultiplicity == RelationshipMultiplicity.Many &&
relProperty.FromEnd.RelationshipMultiplicity == RelationshipMultiplicity.Many,
"Expected target end multiplicity to be 'many'. Found " + relProperty + "; multiplicity = " + relProperty.ToEnd.RelationshipMultiplicity);
Node ret = null;
List<Node> joinNodes = new List<Node>(relationshipSets.Count);
List<Var> outputVars = new List<Var>(relationshipSets.Count * 2);
foreach (RelationshipSet r in relationshipSets)
{
Var rsVar;
Var esVar;
Node joinNode = BuildJoinForNavProperty(r, relProperty.ToEnd, out rsVar, out esVar);
joinNodes.Add(joinNode);
outputVars.Add(rsVar);
outputVars.Add(esVar);
}
//
// Build the union-all node
//
Node unionAllNode;
IList<Var> unionAllVars;
m_command.BuildUnionAllLadder(joinNodes, outputVars, out unionAllNode, out unionAllVars);
//
// Now build out the filterOp over the left-side var
//
Node rsSourceRefNode = m_command.CreateNode(m_command.CreatePropertyOp(relProperty.FromEnd),
m_command.CreateNode(m_command.CreateVarRefOp(unionAllVars[0])));
Node predicate = m_command.BuildComparison(OpType.EQ,
sourceRefNode, rsSourceRefNode);
Node filterNode = m_command.CreateNode(m_command.CreateFilterOp(),
unionAllNode, predicate);
//
// Finally, build out a project node that only projects out the entity side
//
Node projectNode = m_command.BuildProject(filterNode, new Var[] { unionAllVars[1] }, new Node[] { });
//
// Build a collectOp over the project node
//
ret = m_command.BuildCollect(projectNode, unionAllVars[1]);
return ret;
}
/// <summary>
/// Rewrite a NavProperty; more generally, consider this a rewrite of DEREF(NAVIGATE(r))
///
/// We handle four cases here, depending on the kind of relationship we're
/// dealing with.
/// - 1:1 relationships
/// - 1:M relationships
/// - N:1 relationships
/// - N:M relationships
///
/// </summary>
/// <param name="navProperty">the navigation property</param>
/// <param name="sourceEntityNode">the input ref to start the traversal</param>
/// <param name="resultType">the result type of the expression</param>
/// <returns>the rewritten tree</returns>
private Node RewriteNavigationProperty(NavigationProperty navProperty,
Node sourceEntityNode, TypeUsage resultType)
{
RelProperty relProperty = new RelProperty(navProperty.RelationshipType, navProperty.FromEndMember, navProperty.ToEndMember);
PlanCompiler.Assert(m_command.IsRelPropertyReferenced(relProperty) || (relProperty.ToEnd.RelationshipMultiplicity == RelationshipMultiplicity.Many),
"Unreferenced rel property? " + relProperty);
// Handle N:1
if ((relProperty.FromEnd.RelationshipMultiplicity == RelationshipMultiplicity.Many) &&
(relProperty.ToEnd.RelationshipMultiplicity != RelationshipMultiplicity.Many))
{
return RewriteManyToOneNavigationProperty(relProperty, sourceEntityNode, resultType);
}
//
// Find the list of all relationships that could satisfy this relationship
// If we find no matching relationship set, simply return a null node / empty collection
//
List<RelationshipSet> relationshipSets = GetRelationshipSets(relProperty.Relationship);
if (relationshipSets.Count == 0)
{
// return an empty set / null node
if (relProperty.ToEnd.RelationshipMultiplicity == RelationshipMultiplicity.Many)
{
return m_command.CreateNode(m_command.CreateNewMultisetOp(resultType));
}
return m_command.CreateNode(m_command.CreateNullOp(resultType));
}
// Build out a ref over the source entity
Node sourceRefNode = m_command.CreateNode(
m_command.CreateGetEntityRefOp(relProperty.FromEnd.TypeUsage),
sourceEntityNode);
// Hanlde the 1:M and N:M cases
if (relProperty.ToEnd.RelationshipMultiplicity == RelationshipMultiplicity.Many)
{
// Handle N:M
if (relProperty.FromEnd.RelationshipMultiplicity == RelationshipMultiplicity.Many)
{
return RewriteManyToManyNavigationProperty(relProperty, relationshipSets, sourceRefNode);
}
// Handle 1:M
return RewriteOneToManyNavigationProperty(relProperty, relationshipSets, sourceRefNode);
}
// Handle 1:1
return RewriteOneToOneNavigationProperty(relProperty, relationshipSets,sourceRefNode);
}
#endregion
#region visitor methods
#region ScalarOps
/// <summary>
/// Default handler for scalar Ops. Simply traverses the children,
/// and also identifies any structured types along the way
/// </summary>
/// <param name="op">the ScalarOp</param>
/// <param name="n">current subtree</param>
/// <returns>the possibly modified node</returns>
protected override Node VisitScalarOpDefault(ScalarOp op, Node n)
{
VisitChildren(n); // visit my children
// keep track of referenced types
AddTypeReference(op.Type);
return n;
}
/// <summary>
/// Rewrite a DerefOp subtree. We have two cases to consider here.
/// We call RewriteDerefOp to return a subtree (and an optional outputVar).
/// If the outputVar is null, then we simply return the subtree produced by those calls.
/// Otherwise, we add the subtree to the "parent" relop (to be outer-applied), and then use the outputVar
/// in its place.
///
/// As an example,
/// select deref(e) from T
/// gets rewritten into
/// select v from T OuterApply X
/// where X is the subtree returned from the RewriteXXX calls, and "v" is the output var produced by X
///
/// </summary>
/// <param name="op">the derefOp</param>
/// <param name="n">the deref subtree</param>
/// <returns>the rewritten tree</returns>
public override Node Visit(DerefOp op, Node n)
{
Var outputVar;
VisitScalarOpDefault(op, n);
Node ret = RewriteDerefOp(n, op, out outputVar);
ret = VisitNode(ret);
if (outputVar != null)
{
ret = AddSubqueryToParentRelOp(outputVar, ret);
}
return ret;
}
/// <summary>
/// Processing for an ElementOp. Replaces this by the corresponding Var from
/// the subquery, and adds the subquery to the list of currently tracked subqueries
/// </summary>
/// <param name="op">the elementOp</param>
/// <param name="n">current subtree</param>
/// <returns>the Var from the subquery</returns>
public override Node Visit(ElementOp op, Node n)
{
VisitScalarOpDefault(op, n); // default processing
// get to the subquery...
Node subQueryRelOp = n.Child0;
ProjectOp projectOp = (ProjectOp)subQueryRelOp.Op;
PlanCompiler.Assert(projectOp.Outputs.Count == 1, "input to ElementOp has more than one output var?");
Var projectVar = projectOp.Outputs.First;
Node ret = AddSubqueryToParentRelOp(projectVar, subQueryRelOp);
return ret;
}
/// <summary>
/// Mark Normalization as needed
/// </summary>
/// <param name="op"></param>
/// <param name="n"></param>
/// <returns></returns>
public override Node Visit(ExistsOp op, Node n)
{
m_compilerState.MarkPhaseAsNeeded(PlanCompilerPhase.Normalization);
return base.Visit(op, n);
}
/// <summary>
/// Visit a function call expression. If function is mapped, expand and visit the mapping expression.
/// If this is TVF or a collection aggregate function, NestPullUp and Normalization are needed.
/// </summary>
/// <param name="op"></param>
/// <param name="n"></param>
/// <returns></returns>
public override Node Visit(FunctionOp op, Node n)
{
if (op.Function.IsFunctionImport)
{
PlanCompiler.Assert(op.Function.IsComposableAttribute, "Cannot process a non-composable function inside query tree composition.");
FunctionImportMapping functionImportMapping = null;
if (!m_command.MetadataWorkspace.TryGetFunctionImportMapping(op.Function, out functionImportMapping))
{
throw EntityUtil.Metadata(System.Data.Entity.Strings.EntityClient_UnmappedFunctionImport(op.Function.FullName));
}
PlanCompiler.Assert(functionImportMapping is FunctionImportMappingComposable, "Composable function import must have corresponding mapping.");
var functionImportMappingComposable = (FunctionImportMappingComposable)functionImportMapping;
// Visit children (function call arguments) before processing the function view.
// Visiting argument trees before the view tree is required because we want to process them first
// outside of the context of the view. For example if an argument tree contains a free-floating entity-type constructor
// and the function mapping scopes the function results to a particular entity set, we don't want
// the free-floating constructor to be auto-scoped to this set. So we process the argument first, it will
// scope the constructor to the null scope and which guarantees that this constructor will not be rescoped after the argument
// tree is embedded into the function view inside the functionMapping.GetInternalTree(...) call.
VisitChildren(n);
// Get the mapping view of the function.
Node ret = functionImportMappingComposable.GetInternalTree(m_command, n.Children);
// Push the entity type scope, if any, before processing the view.
if (op.Function.EntitySet != null)
{
m_entityTypeScopes.Push(op.Function.EntitySet);
AddEntitySetReference(op.Function.EntitySet);
PlanCompiler.Assert(functionImportMappingComposable.TvfKeys != null && functionImportMappingComposable.TvfKeys.Length > 0, "Function imports returning entities must have inferred keys.");
if (!m_tvfResultKeys.ContainsKey(functionImportMappingComposable.TargetFunction))
{
m_tvfResultKeys.Add(functionImportMappingComposable.TargetFunction, functionImportMappingComposable.TvfKeys);
}
}
// Rerun the processor over the resulting subtree.
ret = VisitNode(ret);
// Remove the entity type scope, if any.
if (op.Function.EntitySet != null)
{
var scope = m_entityTypeScopes.Pop();
PlanCompiler.Assert(scope == op.Function.EntitySet, "m_entityTypeScopes stack is broken");
}
return ret;
}
else
{
PlanCompiler.Assert(op.Function.EntitySet == null, "Entity type scope is not supported on functions that aren't mapped.");
// If this is TVF or a collection aggregate, function NestPullUp and Normalization are needed.
if (TypeSemantics.IsCollectionType(op.Type) || PlanCompilerUtil.IsCollectionAggregateFunction(op, n))
{
m_compilerState.MarkPhaseAsNeeded(PlanCompilerPhase.NestPullup);
m_compilerState.MarkPhaseAsNeeded(PlanCompilerPhase.Normalization);
}
return base.Visit(op, n);
}
}
/// <summary>
/// Default processing.
/// In addition, if the case statement is of the shape
/// case when X then NULL else Y, or
/// case when X then Y else NULL,
/// where Y is of row type and the types of the input CaseOp, the NULL and Y are the same,
/// marks that type as needing a null sentinel.
/// This allows in NominalTypeElimination the case op to be pushed inside Y's null sentinel.
/// </summary>
/// <param name="op"></param>
/// <param name="n"></param>
/// <returns></returns>
public override Node Visit(CaseOp op, Node n)
{
VisitScalarOpDefault(op, n);
//special handling to enable optimization
bool thenClauseIsNull;
if (PlanCompilerUtil.IsRowTypeCaseOpWithNullability(op, n, out thenClauseIsNull))
{
//Add a null sentinel for the row type
m_typesNeedingNullSentinel.Add(op.Type.EdmType.Identity);
}
return n;
}
/// <summary>
/// Special processing for ConditionalOp is handled by <see cref="ProcessConditionalOp"/>
/// </summary>
/// <param name="op"></param>
/// <param name="n"></param>
/// <returns></returns>
public override Node Visit(ConditionalOp op, Node n)
{
VisitScalarOpDefault(op, n);
ProcessConditionalOp(op, n);
return n;
}
/// <summary>
/// If it is a IsNull op over a row type or a complex type mark the type as needing a null sentinel.
/// </summary>
/// <param name="op"></param>
/// <param name="n"></param>
private void ProcessConditionalOp(ConditionalOp op, Node n)
{
if (op.OpType == OpType.IsNull && TypeSemantics.IsRowType(n.Child0.Op.Type) || TypeSemantics.IsComplexType(n.Child0.Op.Type))
{
StructuredTypeNullabilityAnalyzer.MarkAsNeedingNullSentinel(m_typesNeedingNullSentinel, n.Child0.Op.Type);
}
}
#region PropertyOp Handling
/// <summary>
/// Validates that the nav property agrees with the underlying relationship
/// </summary>
/// <param name="op">the Nav PropertyOp</param>
/// <param name="n">the subtree</param>
private void ValidateNavPropertyOp(PropertyOp op, Node n)
{
NavigationProperty navProperty = (NavigationProperty)op.PropertyInfo;
//
// If the result of the expanded form of the navigation property is not compatible with
// the declared type of the property, then the navigation property is invalid in the
// context of this command tree's metadata workspace.
//
TypeUsage resultType = navProperty.ToEndMember.TypeUsage;
if (TypeSemantics.IsReferenceType(resultType))
{
resultType = TypeHelpers.GetElementTypeUsage(resultType);
}
if (navProperty.ToEndMember.RelationshipMultiplicity == RelationshipMultiplicity.Many)
{
resultType = TypeUsage.Create(resultType.EdmType.GetCollectionType());
}
if (!TypeSemantics.IsStructurallyEqualOrPromotableTo(resultType, op.Type))
{
throw EntityUtil.Metadata(System.Data.Entity.Strings.EntityClient_IncompatibleNavigationPropertyResult(
navProperty.DeclaringType.FullName,
navProperty.Name
)
);
}
}
/// <summary>
/// Rewrite a PropertyOp subtree for a nav property
/// <see cref="RewriteNavigationProperty"/> does the heavy lifting
/// </summary>
/// <param name="op">the PropertyOp</param>
/// <param name="n">the current node</param>
/// <returns>the rewritten subtree</returns>
private Node VisitNavPropertyOp(PropertyOp op, Node n)
{
ValidateNavPropertyOp(op, n);
//
// In this special case we visit the parent before the child to avoid TSQL regressions.
// In particular, a subquery coming out of the child would need to be attached to the closest rel-op parent
// and if the parent is already visited that rel op parent would be part of the subtree resulting from the parent.
// If the parent is not visited it would be a rel op parent higher in the tree (also valid), and leaves less room
// for join elimination.
// The original out-of-order visitation was put in place to work around a bug that has been fixed.
//
bool visitChildLater = IsNavigationPropertyOverVarRef(n.Child0);
if (!visitChildLater)
{
VisitScalarOpDefault(op, n);
}
NavigationProperty navProperty = (NavigationProperty)op.PropertyInfo;
Node ret = RewriteNavigationProperty(navProperty, n.Child0, op.Type);
ret = VisitNode(ret);
return ret;
}
/// <summary>
/// Is the given node of shape NavigationProperty(SoftCast(VarRef)), or NavigationProperty(VarRef)
/// </summary>
/// <param name="n"></param>
/// <returns></returns>
private static bool IsNavigationPropertyOverVarRef(Node n)
{
if (n.Op.OpType != OpType.Property || (!Helper.IsNavigationProperty(((PropertyOp)n.Op).PropertyInfo)))
{
return false;
}
Node currentNode = n.Child0;
if (currentNode.Op.OpType == OpType.SoftCast)
{
currentNode = currentNode.Child0;
}
return currentNode.Op.OpType == OpType.VarRef;
}
/// <summary>
/// Rewrite a PropertyOp subtree.
///
/// If the PropertyOp represents a simple property (ie) not a navigation property, we simply call
/// VisitScalarOpDefault() and return. Otherwise, we call VisitNavPropertyOp and return the result from
/// that function
///
/// </summary>
/// <param name="op">the PropertyOp</param>
/// <param name="n">the PropertyOp subtree</param>
/// <returns>the rewritten tree</returns>
public override Node Visit(PropertyOp op, Node n)
{
Node ret;
if (Helper.IsNavigationProperty(op.PropertyInfo))
{
ret = VisitNavPropertyOp(op, n);
}
else
{
ret = VisitScalarOpDefault(op, n);
}
return ret;
}
#endregion
/// <summary>
/// Handler for a RefOp.
/// Keeps track of the entityset
/// </summary>
/// <param name="op">the RefOp</param>
/// <param name="n">current RefOp subtree</param>
/// <returns>current subtree</returns>
public override Node Visit(RefOp op, Node n)
{
VisitScalarOpDefault(op, n); // use default processing
AddEntitySetReference(op.EntitySet); // add to list of references
return n;
}
/// <summary>
/// Handler for a TreatOp.
/// Rewrites the operator if the argument is guaranteed to be of type
/// op.
/// </summary>
/// <param name="op">Current TreatOp</param>
/// <param name="n">Current subtree</param>
/// <returns>Current subtree</returns>
public override Node Visit(TreatOp op, Node n)
{
n = base.Visit(op, n);
// See if TreatOp can be rewritten (if it's not polymorphic)
if (CanRewriteTypeTest(op.Type.EdmType, n.Child0.Op.Type.EdmType))
{
// Return argument directly (if the argument is null, 'treat as' also returns null;
// if the argument is not null, it's guaranteed to be of the correct type)
return n.Child0;
}
return n;
}
/// <summary>
/// Handler for an IsOfOp.
/// Keeps track of the IsOfType (if it is a structured type) and rewrites the
/// operator if the argument is guaranteed to be of type op.IsOfType
/// </summary>
/// <param name="op">Current IsOfOp</param>
/// <param name="n">Current subtree</param>
/// <returns>Current subtree</returns>
public override Node Visit(IsOfOp op, Node n)
{
VisitScalarOpDefault(op, n); // default handling first
// keep track of any structured types
AddTypeReference(op.IsOfType);
// See if the IsOfOp can be rewritten (if it's not polymorphic)
if (CanRewriteTypeTest(op.IsOfType.EdmType, n.Child0.Op.Type.EdmType))
{
n = RewriteIsOfAsIsNull(op, n);
}
// For IsOfOnly(abstract type), suppress DiscriminatorMaps since no explicit type id is available for
// abstract types.
if (op.IsOfOnly && op.IsOfType.EdmType.Abstract)
{
m_suppressDiscriminatorMaps = true;
}
return n;
}
// Determines whether a type test expression can be rewritten. Returns true of the
// argument type is guaranteed to implement "testType" (if the argument is non-null).
private bool CanRewriteTypeTest(EdmType testType, EdmType argumentType)
{
// The rewrite only proceeds if the types are the same. If they are not,
// it suggests either that the input result is polymorphic (in which case if OfType
// should be preserved) or the types are incompatible (which is caught
// elsewhere)
if (!testType.EdmEquals(argumentType))
{
return false;
}
// If the IsOfType is non-polymorphic (no base or derived types) the rewrite
// is possible.
if (null != testType.BaseType)
{
return false;
}
// Count sub types
int subTypeCount = 0;
foreach (EdmType subType in MetadataHelper.GetTypeAndSubtypesOf(testType, m_command.MetadataWorkspace, true /*includeAbstractTypes*/))
{
subTypeCount++;
if (2 == subTypeCount) { break; }
}
return 1 == subTypeCount; // no children types
}
// Translates
// 'R is of T'
// to
// '(case when not (R is null) then True else null end) = True'
//
// Input requirements:
//
// - IsOfOp and argument to same must be in the same hierarchy.
// - IsOfOp and argument must have the same type
// - IsOfOp.IsOfType may not have super- or sub- types (validate
// using CanRewriteTypeTest)
//
// Design requirements:
//
// - Must return true if the record exists
// - Must return null if it does not
// - Must be in predicate form to avoid confusing SQL gen
//
// The translation assumes R is of T when R is non null.
private Node RewriteIsOfAsIsNull(IsOfOp op, Node n)
{
// construct 'R is null' predicate
ConditionalOp isNullOp = m_command.CreateConditionalOp(OpType.IsNull);
Node isNullNode = m_command.CreateNode(isNullOp, n.Child0);
// Process the IsNull node to make sure a null sentinel gets added if needed
ProcessConditionalOp(isNullOp, isNullNode);
// construct 'not (R is null)' predicate
ConditionalOp notOp = m_command.CreateConditionalOp(OpType.Not);
Node notNode = m_command.CreateNode(notOp, isNullNode);
// construct 'True' result
ConstantBaseOp trueOp = m_command.CreateConstantOp(op.Type, true);
Node trueNode = m_command.CreateNode(trueOp);
// construct 'null' default result
NullOp nullOp = m_command.CreateNullOp(op.Type);
Node nullNode = m_command.CreateNode(nullOp);
// create case statement
CaseOp caseOp = m_command.CreateCaseOp(op.Type);
Node caseNode = m_command.CreateNode(caseOp, notNode, trueNode, nullNode);
// create 'case = true' operator
ComparisonOp equalsOp = m_command.CreateComparisonOp(OpType.EQ);
Node equalsNode = m_command.CreateNode(equalsOp, caseNode, trueNode);
return equalsNode;
}
/// <summary>
/// Rewrite a NavigateOp subtree.
/// We call RewriteNavigateOp to return a subtree (and an optional outputVar).
/// If the outputVar is null, then we simply return the subtree produced by those calls.
/// Otherwise, we add the subtree to the "parent" relop (to be outer-applied), and then use the outputVar
/// in its place.
///
/// As an example,
/// select navigate(e) from T
/// gets rewritten into
/// select v from T OuterApply X
/// where X is the subtree returned from the RewriteXXX calls, and "v" is the output var produced by X
///
/// </summary>
/// <param name="op">the navigateOp</param>
/// <param name="n">the navigateOp subtree</param>
/// <returns>the rewritten tree</returns>
public override Node Visit(NavigateOp op, Node n)
{
VisitScalarOpDefault(op, n);
Var outputVar;
Node ret = RewriteNavigateOp(n, op, out outputVar);
ret = VisitNode(ret);
// Move subquery to parent relop if necessary
if (outputVar != null)
{
ret = AddSubqueryToParentRelOp(outputVar, ret);
}
return ret;
}
/// <summary>
/// Returns the current entity set scope, if any, for an entity type constructor.
/// The scope defines the result of the construtor as a scoped entity type.
/// </summary>
private EntitySet GetCurrentEntityTypeScope()
{
if (m_entityTypeScopes.Count == 0)
{
return null;
}
return m_entityTypeScopes.Peek();
}
/// <summary>
/// Find the relationshipset that matches the current entityset + from/to roles
/// </summary>
/// <param name="entitySet"></param>
/// <param name="relProperty"></param>
/// <returns></returns>
private RelationshipSet FindRelationshipSet(EntitySetBase entitySet, RelProperty relProperty)
{
foreach (EntitySetBase es in entitySet.EntityContainer.BaseEntitySets)
{
AssociationSet rs = es as AssociationSet;
if (rs != null &&
rs.ElementType.EdmEquals(relProperty.Relationship) &&
rs.AssociationSetEnds[relProperty.FromEnd.Identity].EntitySet.EdmEquals(entitySet))
{
return rs;
}
}
return null;
}
/// <summary>
/// Find the position of a property in a type.
/// Positions start at zero, and a supertype's properties precede the current
/// type's properties
/// </summary>
/// <param name="type">the type in question</param>
/// <param name="member">the member to lookup</param>
/// <returns>the position of the member in the type (0-based)</returns>
private int FindPosition(EdmType type, EdmMember member)
{
int pos = 0;
foreach (EdmMember m in TypeHelpers.GetAllStructuralMembers(type))
{
if (m.EdmEquals(member))
{
return pos;
}
pos++;
}
PlanCompiler.Assert(false, "Could not find property " + member + " in type " + type.Name);
return -1;
}
/// <summary>
/// Build out an expression (NewRecord) that corresponds to the key properties
/// of the passed-in entity constructor
///
/// This function simply looks up the key properties of the entity type, and then
/// identifies the arguments to the constructor corresponding to those
/// properties, and then slaps on a record wrapper over those expressions.
///
/// No copies/clones are performed. That's the responsibility of the caller
///
/// </summary>
/// <param name="op">the entity constructor op</param>
/// <param name="n">the corresponding subtree</param>
/// <returns>the key expression</returns>
private Node BuildKeyExpressionForNewEntityOp(Op op, Node n)
{
PlanCompiler.Assert(op.OpType == OpType.NewEntity || op.OpType == OpType.DiscriminatedNewEntity,
"BuildKeyExpression: Unexpected OpType:" + op.OpType);
int offset = (op.OpType == OpType.DiscriminatedNewEntity) ? 1 : 0;
EntityTypeBase entityType = (EntityTypeBase)op.Type.EdmType;
List<Node> keyFields = new List<Node>();
List<KeyValuePair<string, TypeUsage>> keyFieldTypes = new List<KeyValuePair<string, TypeUsage>>();
foreach (EdmMember k in entityType.KeyMembers)
{
int pos = FindPosition(entityType, k) + offset;
PlanCompiler.Assert(n.Children.Count > pos, "invalid position " + pos + "; total count = " + n.Children.Count);
keyFields.Add(n.Children[pos]);
keyFieldTypes.Add(new KeyValuePair<string, TypeUsage>(k.Name, k.TypeUsage));
}
TypeUsage keyExprType = TypeHelpers.CreateRowTypeUsage(keyFieldTypes, true);
NewRecordOp keyOp = m_command.CreateNewRecordOp(keyExprType);
Node keyNode = m_command.CreateNode(keyOp, keyFields);
return keyNode;
}
/// <summary>
/// Build out an expression corresponding to the rel-property.
///
/// We create a subquery that looks like
/// (select r
/// from RS r
/// where GetRefKey(r.FromEnd) = myKey)
///
/// RS is the single relationship set that corresponds to the given entityset/rel-property pair
/// FromEnd - is the source end of the relationship
/// myKey - is the key expression of the entity being constructed
///
/// NOTE: We always clone "myKey" before use.
///
/// We then convert it into a scalar subquery, and extract out the ToEnd property from
/// the output var of the subquery. (Should we do this inside the subquery itself?)
///
/// If no single relationship-set is found, we return a NULL instead.
/// </summary>
/// <param name="entitySet">entity set that logically holds instances of the entity we're building</param>
/// <param name="relProperty">the rel-property we're trying to build up</param>
/// <param name="keyExpr">the "key" of the entity instance</param>
/// <returns>the rel-property expression</returns>
private Node BuildRelPropertyExpression(EntitySetBase entitySet, RelProperty relProperty,
Node keyExpr)
{
//
// Make a copy of the current key expression
//
keyExpr = OpCopier.Copy(m_command, keyExpr);
//
// Find the relationship set corresponding to this entityset (and relProperty)
// Return a null ref, if we can't find one
//
RelationshipSet relSet = FindRelationshipSet(entitySet, relProperty);
if (relSet == null)
{
return m_command.CreateNode(m_command.CreateNullOp(relProperty.ToEnd.TypeUsage));
}
ScanTableOp scanTableOp = m_command.CreateScanTableOp(Command.CreateTableDefinition(relSet));
PlanCompiler.Assert(scanTableOp.Table.Columns.Count == 1,
"Unexpected column count for table:" + scanTableOp.Table.TableMetadata.Extent + "=" + scanTableOp.Table.Columns.Count);
Var scanTableVar = scanTableOp.Table.Columns[0];
Node scanNode = m_command.CreateNode(scanTableOp);
Node sourceEndNode = m_command.CreateNode(
m_command.CreatePropertyOp(relProperty.FromEnd),
m_command.CreateNode(m_command.CreateVarRefOp(scanTableVar)));
Node predicateNode = m_command.BuildComparison(OpType.EQ,
keyExpr,
m_command.CreateNode(m_command.CreateGetRefKeyOp(keyExpr.Op.Type), sourceEndNode));
Node filterNode = m_command.CreateNode(m_command.CreateFilterOp(),
scanNode, predicateNode);
//
// Process the node, and then add this as a subquery to the parent relop
//
Node ret = VisitNode(filterNode);
ret = AddSubqueryToParentRelOp(scanTableVar, ret);
//
// Now extract out the target end property
//
ret = m_command.CreateNode(
m_command.CreatePropertyOp(relProperty.ToEnd),
ret);
return ret;
}
/// <summary>
/// Given an entity constructor (NewEntityOp, DiscriminatedNewEntityOp), build up
/// the list of rel-property expressions.
///
/// Walks through the list of relevant rel-properties, and builds up expressions
/// (using BuildRelPropertyExpression) for each rel-property that does not have
/// an expression already built (preBuiltExpressions)
/// </summary>
/// <param name="entitySet">entity set that holds instances of the entity we're building</param>
/// <param name="relPropertyList">the list of relevant rel-properties for this entity type</param>
/// <param name="prebuiltExpressions">the prebuilt rel-property expressions</param>
/// <param name="keyExpr">the key of the entity instance</param>
/// <returns>a list of rel-property expressions (lines up 1-1 with 'relPropertyList')</returns>
private IEnumerable<Node> BuildAllRelPropertyExpressions(EntitySetBase entitySet,
List<RelProperty> relPropertyList,
Dictionary<RelProperty, Node> prebuiltExpressions,
Node keyExpr)
{
foreach (RelProperty r in relPropertyList)
{
Node relPropNode;
if (!prebuiltExpressions.TryGetValue(r, out relPropNode))
{
relPropNode = BuildRelPropertyExpression(entitySet, r, keyExpr);
}
yield return relPropNode;
}
}
/// <summary>
/// Handler for NewEntityOp.
/// Assignes scope to the entity constructor if it hasn't been assigned before.
/// </summary>
/// <param name="op">the NewEntityOp</param>
/// <param name="n">the node tree corresponding to the op</param>
/// <returns>rewritten tree</returns>
public override Node Visit(NewEntityOp op, Node n)
{
// If this is not an entity type constructor, or it's been already scoped,
// then just do the default processing.
if (op.Scoped || op.Type.EdmType.BuiltInTypeKind != BuiltInTypeKind.EntityType)
{
return base.Visit(op, n);
}
EntityType entityType = (EntityType)op.Type.EdmType;
EntitySet scope = GetCurrentEntityTypeScope();
List<RelProperty> relProperties;
List<Node> newChildren;
if (scope == null)
{
m_freeFloatingEntityConstructorTypes.Add(entityType);
// SQLBUDT #546546: Qmv/Umv tests Assert and throws in plan compiler in association tests.
// If this Entity constructor is not within a view then there should not be any RelProps
// specified on the NewEntityOp - the eSQL WITH RELATIONSHIP clauses that would cause such
// RelProps to be added is only enabled when parsing in the user or generated view mode.
PlanCompiler.Assert(op.RelationshipProperties == null ||
op.RelationshipProperties.Count == 0,
"Related Entities cannot be specified for Entity constructors that are not part of the Query Mapping View for an Entity Set.");
// Default processing.
VisitScalarOpDefault(op, n);
relProperties = op.RelationshipProperties;
newChildren = n.Children;
}
else
{
//
// Note: We don't do the default processing first to avoid adding references to types and entity sets
// that may only be used in pre-built rel property expressions that may not be needed.
//
//
// Find the relationship properties for this entitytype (and entity set)
//
relProperties = new List<RelProperty>(m_relPropertyHelper.GetRelProperties(entityType));
// Remove pre-built rel property expressions that would not be needed to avoid
// unnecessary adding references to types and entity sets during default processing
int j = op.RelationshipProperties.Count - 1;
List<RelProperty> copiedRelPropList = new List<RelProperty>(op.RelationshipProperties);
for (int i = n.Children.Count - 1; i >= entityType.Properties.Count; i--, j--)
{
if (!relProperties.Contains(op.RelationshipProperties[j]))
{
n.Children.RemoveAt(i);
copiedRelPropList.RemoveAt(j);
}
}
// Default processing.
VisitScalarOpDefault(op, n);
//
// Ok, now, I have to build out some relationship properties that
// haven't been specified
//
Node keyExpr = BuildKeyExpressionForNewEntityOp(op, n);
//
// Find the list of rel properties that have already been specified
//
Dictionary<RelProperty, Node> prebuiltRelPropertyExprs = new Dictionary<RelProperty, Node>();
j = 0;
for (int i = entityType.Properties.Count; i < n.Children.Count; i++, j++)
{
prebuiltRelPropertyExprs[copiedRelPropList[j]] = n.Children[i];
}
//
// Next, rebuild the list of children - includes expressions for each rel property
//
newChildren = new List<Node>();
for (int i = 0; i < entityType.Properties.Count; i++)
{
newChildren.Add(n.Children[i]);
}
foreach (Node relPropNode in BuildAllRelPropertyExpressions(scope, relProperties, prebuiltRelPropertyExprs, keyExpr))
{
newChildren.Add(relPropNode);
}
}
//
// Finally, build out the newOp.
//
Op newEntityOp = m_command.CreateScopedNewEntityOp(op.Type, relProperties, scope);
Node newNode = m_command.CreateNode(newEntityOp, newChildren);
return newNode;
}
/// <summary>
/// Tracks discriminator metadata so that is can be used when constructing
/// StructuredTypeInfo.
/// </summary>
public override Node Visit(DiscriminatedNewEntityOp op, Node n)
{
HashSet<RelProperty> relPropertyHashSet = new HashSet<RelProperty>();
List<RelProperty> relProperties = new List<RelProperty>();
//
// add references to each type produced by this node
// Also, get the set of rel-properties for each of the types
//
foreach (var discriminatorTypePair in op.DiscriminatorMap.TypeMap)
{
EntityTypeBase entityType = discriminatorTypePair.Value;
AddTypeReference(TypeUsage.Create(entityType));
foreach (RelProperty relProperty in m_relPropertyHelper.GetRelProperties(entityType))
{
relPropertyHashSet.Add(relProperty);
}
}
relProperties = new List<RelProperty>(relPropertyHashSet);
VisitScalarOpDefault(op, n);
//
// Now build out the set of missing rel-properties (if any)
//
// first, build the key expression
Node keyExpr = BuildKeyExpressionForNewEntityOp(op, n);
List<Node> newChildren = new List<Node>();
int firstRelPropertyNodeOffset = n.Children.Count - op.RelationshipProperties.Count;
for (int i = 0; i < firstRelPropertyNodeOffset; i++)
{
newChildren.Add(n.Children[i]);
}
//
// Find the list of rel properties that have already been specified
//
Dictionary<RelProperty, Node> prebuiltRelPropertyExprs = new Dictionary<RelProperty, Node>();
for (int i = firstRelPropertyNodeOffset, j = 0; i < n.Children.Count; i++, j++)
{
prebuiltRelPropertyExprs[op.RelationshipProperties[j]] = n.Children[i];
}
//
// Fill in the missing pieces
//
foreach (Node relPropNode in BuildAllRelPropertyExpressions(op.EntitySet, relProperties, prebuiltRelPropertyExprs, keyExpr))
{
newChildren.Add(relPropNode);
}
Op newEntityOp = m_command.CreateDiscriminatedNewEntityOp(op.Type, op.DiscriminatorMap, op.EntitySet, relProperties);
Node newNode = m_command.CreateNode(newEntityOp, newChildren);
return newNode;
}
/// <summary>
/// Handles a newMultiset constructor. Converts this into
/// select a from dual union all select b from dual union all ...
/// Handles a NewMultiset constructor, i.e. {x, y, z}
/// 1. Empty multiset constructors are simply converted into:
///
/// select x from singlerowtable as x where false
///
/// 2. Mulltset constructors with only one element or with multiple elements all of
/// which are constants or nulls are converted into:
///
/// select x from dual union all select y from dual union all select z
///
/// 3. All others are converted into:
///
/// select case when d = 0 then x when d = 1 then y else z end
/// from ( select 0 as d from single_row_table
/// union all
/// select 1 as d from single_row_table
/// union all
/// select 2 as d from single_row_table )
///
/// NOTE: The translation for 2 is valid for 3 too. We choose different translation
/// in order to avoid correlation inside the union all,
/// which would prevent us from removing apply operators
///
/// Do this before processing the children, and then
/// call Visit on the result to handle the elements
/// </summary>
/// <param name="op">the new instance op</param>
/// <param name="n">the current subtree</param>
/// <returns>the modified subtree</returns>
public override Node Visit(NewMultisetOp op, Node n)
{
Node resultNode = null;
Var resultVar = null;
CollectionType collectionType = TypeHelpers.GetEdmType<CollectionType>(op.Type);
//
// Empty multiset constructors are simply converted into
// Project(Filter(SingleRowTableOp(), false)
//
if (!n.HasChild0)
{
Node singleRowTableNode = m_command.CreateNode(m_command.CreateSingleRowTableOp());
Node filterNode = m_command.CreateNode(m_command.CreateFilterOp(),
singleRowTableNode,
m_command.CreateNode(m_command.CreateFalseOp()));
Node fakeChild = m_command.CreateNode(m_command.CreateNullOp(collectionType.TypeUsage));
Var newVar;
Node projectNode = m_command.BuildProject(filterNode, fakeChild, out newVar);
resultNode = projectNode;
resultVar = newVar;
}
//
// Multiset constructors with only one elment or with multiple elments all of
// which are constants or nulls are converted into:
//
// UnionAll(Project(SingleRowTable, e1), Project(SingleRowTable, e2), ...)
//
// The degenerate case when the collection has only one element does not require an
// outer unionAll node
//
else if (n.Children.Count == 1 || AreAllConstantsOrNulls(n.Children))
{
List<Node> inputNodes = new List<Node>();
List<Var> inputVars = new List<Var>();
foreach (Node chi in n.Children)
{
Node singleRowTableNode = m_command.CreateNode(m_command.CreateSingleRowTableOp());
Var newVar;
Node projectNode = m_command.BuildProject(singleRowTableNode, chi, out newVar);
inputNodes.Add(projectNode);
inputVars.Add(newVar);
}
// Build the union-all ladder
m_command.BuildUnionAllLadder(inputNodes, inputVars, out resultNode, out resultVar);
}
//
// All other cases:
//
// select case when d = 0 then x when d = 1 then y else z end
// from ( select 0 as d from single_row_table
// union all
// select 1 as d from single_row_table
// union all
// select 2 as d from single_row_table )
//
else
{
List<Node> inputNodes = new List<Node>();
List<Var> inputVars = new List<Var>();
//Create the union all lather first
for (int i = 0; i < n.Children.Count; i++)
{
Node singleRowTableNode = m_command.CreateNode(m_command.CreateSingleRowTableOp());
// the discriminator for this branch
Node discriminatorNode = m_command.CreateNode(m_command.CreateInternalConstantOp(m_command.IntegerType, i));
Var newVar;
Node projectNode = m_command.BuildProject(singleRowTableNode, discriminatorNode, out newVar);
inputNodes.Add(projectNode);
inputVars.Add(newVar);
}
// Build the union-all ladder now
m_command.BuildUnionAllLadder(inputNodes, inputVars, out resultNode, out resultVar);
//Now create the case statement for the projection
List<Node> caseArgNodes = new List<Node>(n.Children.Count * 2 + 1);
for (int i = 0; i < n.Children.Count; i++)
{
//For all but the last we need a when
if (i != (n.Children.Count - 1))
{
ComparisonOp equalsOp = m_command.CreateComparisonOp(OpType.EQ);
Node whenNode = m_command.CreateNode(equalsOp,
m_command.CreateNode(m_command.CreateVarRefOp(resultVar)),
m_command.CreateNode(
m_command.CreateConstantOp(m_command.IntegerType, i)));
caseArgNodes.Add(whenNode);
}
//Add the then/else node
caseArgNodes.Add(n.Children[i]);
}
//Create the project
Node caseNode = m_command.CreateNode(m_command.CreateCaseOp(collectionType.TypeUsage), caseArgNodes);
resultNode = m_command.BuildProject(resultNode, caseNode, out resultVar);
}
// So, I've finally built up a complex query corresponding to the constructor.
// Now, cap this with a physicalprojectOp, and then with a CollectOp
PhysicalProjectOp physicalProjectOp = m_command.CreatePhysicalProjectOp(resultVar);
Node physicalProjectNode = m_command.CreateNode(physicalProjectOp, resultNode);
CollectOp collectOp = m_command.CreateCollectOp(op.Type);
Node collectNode = m_command.CreateNode(collectOp, physicalProjectNode);
return VisitNode(collectNode);
}
/// <summary>
/// Returns true if each node in the list is either a constant or a null
/// </summary>
/// <param name="nodes"></param>
/// <returns></returns>
private bool AreAllConstantsOrNulls(List<Node> nodes)
{
foreach (Node node in nodes)
{
if (node.Op.OpType != OpType.Constant && node.Op.OpType != OpType.Null)
{
return false;
}
}
return true;
}
/// <summary>
/// Default processing for a CollectOp. But make sure that we
/// go through the NestPullUp phase
/// </summary>
/// <param name="op"></param>
/// <param name="n"></param>
/// <returns></returns>
public override Node Visit(CollectOp op, Node n)
{
m_compilerState.MarkPhaseAsNeeded(PlanCompilerPhase.NestPullup);
return VisitScalarOpDefault(op, n);
}
#endregion
#region RelOps
private void HandleTableOpMetadata(ScanTableBaseOp op)
{
// add to the list of referenced entitysets
EntitySet entitySet = op.Table.TableMetadata.Extent as EntitySet;
if (entitySet != null)
{
// If entitySet is an association set, the appropriate entity set references will be registered inside Visit(RefOp, Node).
AddEntitySetReference(entitySet);
}
TypeUsage elementType = TypeUsage.Create(op.Table.TableMetadata.Extent.ElementType);
// add to the list of structured types
AddTypeReference(elementType);
}
/// <summary>
/// Visits a "table" expression - performs view expansion on the table (if appropriate),
/// and then some additional book-keeping.
///
/// The "ofType" and "includeSubtypes" parameters are optional hints for view expansion, allowing
/// for more customized (and hopefully, more optimal) views. The wasOfTypeSatisfied out parameter
/// tells whether the ofType filter was already handled by the view expansion, or if the caller still
/// needs to deal with it.
///
/// If the "table" is a C-space entityset, then we produce a ScanViewOp
/// tree with the defining query as the only child of the ScanViewOp
///
/// If the table is an S-space entityset, then we still produce a ScanViewOp, but this
/// time, we produce a simple "select * from BaseTable" as the defining
/// query
/// </summary>
/// <param name="scanTableNode">the scanTable node tree</param>
/// <param name="scanTableOp">the scanTableOp</param>
/// <param name="typeFilter">
/// An optional IsOfOp representing a type filter to apply to the scan table; will be set to <c>null</c>
/// if the scan target is expanded to a view that renders the type filter superfluous.
/// </param>
/// <returns></returns>
private Node ProcessScanTable(Node scanTableNode, ScanTableOp scanTableOp, ref IsOfOp typeFilter)
{
HandleTableOpMetadata(scanTableOp);
PlanCompiler.Assert(scanTableOp.Table.TableMetadata.Extent != null, "ScanTableOp must reference a table with an extent");
Node ret = null;
//
// Get simple things out of the way. If we're dealing with an S-space entityset,
// simply return the node
//
if (scanTableOp.Table.TableMetadata.Extent.EntityContainer.DataSpace == DataSpace.SSpace)
{
return scanTableNode;
}
else
{
// "Expand" the C-Space view
ret = ExpandView(scanTableNode, scanTableOp, ref typeFilter);
}
// Rerun the processor over the resulting subtree
ret = VisitNode(ret);
return ret;
}
/// <summary>
/// Processes a ScanTableOp - simply delegates to ProcessScanTableOp
/// </summary>
/// <param name="op">the view op</param>
/// <param name="n">current node tree</param>
/// <returns>the transformed view-op</returns>
public override Node Visit(ScanTableOp op, Node n)
{
IsOfOp nullFilter = null;
return ProcessScanTable(n, op, ref nullFilter);
}
/// <summary>
/// Visitor for a ScanViewOp
/// </summary>
/// <param name="op"></param>
/// <param name="n"></param>
/// <returns></returns>
public override Node Visit(ScanViewOp op, Node n)
{
bool entityTypeScopePushed = false;
if (op.Table.TableMetadata.Extent.BuiltInTypeKind == BuiltInTypeKind.EntitySet)
{
m_entityTypeScopes.Push((EntitySet)op.Table.TableMetadata.Extent);
entityTypeScopePushed = true;
}
HandleTableOpMetadata(op);
// Ideally, I should call this as the first statement, but that was causing too
// many test diffs - because of the order in which the entitytypes/sets
// were being added. There is no semantic difference in calling this here
VisitRelOpDefault(op, n);
if (entityTypeScopePushed)
{
var scope = m_entityTypeScopes.Pop();
PlanCompiler.Assert(scope == op.Table.TableMetadata.Extent, "m_entityTypeScopes stack is broken");
}
return n;
}
/// <summary>
/// Processing for all JoinOps
/// </summary>
/// <param name="op">JoinOp</param>
/// <param name="n">Current subtree</param>
/// <returns></returns>
protected override Node VisitJoinOp(JoinBaseOp op, Node n)
{
// Only LeftOuterJoin and InnerJoin are handled by JoinElimination
if (op.OpType == OpType.InnerJoin || op.OpType == OpType.LeftOuterJoin)
{
m_compilerState.MarkPhaseAsNeeded(PlanCompilerPhase.JoinElimination);
}
// If a subquery was added with an exists node, we have to go througth Normalization
if (base.ProcessJoinOp(op, n))
{
m_compilerState.MarkPhaseAsNeeded(PlanCompilerPhase.Normalization);
}
return n;
}
/// <summary>
/// Perform default relop processing; Also "require" the join-elimination phase
/// </summary>
/// <param name="op"></param>
/// <param name="n"></param>
/// <returns></returns>
protected override Node VisitApplyOp(ApplyBaseOp op, Node n)
{
m_compilerState.MarkPhaseAsNeeded(PlanCompilerPhase.JoinElimination);
return VisitRelOpDefault(op, n);
}
/// <summary>
/// Can I eliminate this sort? I can, if the current path is *not* one of the
/// following
/// TopN(Sort)
/// PhysicalProject(Sort)
///
/// We don't yet handle the TopN variant
/// </summary>
/// <returns></returns>
private bool IsSortUnnecessary()
{
Node ancestor = m_ancestors.Peek();
PlanCompiler.Assert(ancestor != null, "unexpected SortOp as root node?");
if (ancestor.Op.OpType == OpType.PhysicalProject)
{
return false;
}
return true;
}
/// <summary>
/// Visit a SortOp. Eliminate it if the path to this node is not one of
/// PhysicalProject(Sort) or
/// TopN(Sort)
///
/// Otherwise, simply visit the child RelOp
///
/// </summary>
/// <param name="op">Current sortOp</param>
/// <param name="n">current subtree</param>
/// <returns>possibly transformed subtree</returns>
public override Node Visit(SortOp op, Node n)
{
// can I eliminate this sort
if (this.IsSortUnnecessary())
{
return VisitNode(n.Child0);
}
// perform default processing
return VisitRelOpDefault(op, n);
}
/// <summary>
/// Checks to see if this filterOp represents an IS OF (or IS OF ONLY) filter over a ScanTableOp
/// </summary>
/// <param name="n">the filterOp node</param>
/// <param name="ofType">(OUT) the Type to restrict to</param>
/// <param name="isOfOnly">(OUT) was an ONLY clause specified</param>
/// <returns></returns>
private bool IsOfTypeOverScanTable(Node n, out IsOfOp typeFilter)
{
typeFilter = null;
//
// Is the predicate an IsOf predicate
//
IsOfOp isOfOp = n.Child1.Op as IsOfOp;
if (isOfOp == null)
{
return false;
}
//
// Is the Input RelOp a ScanTableOp
//
ScanTableOp scanTableOp = n.Child0.Op as ScanTableOp;
if (scanTableOp == null || scanTableOp.Table.Columns.Count != 1)
{
return false;
}
//
// Is the argument to the IsOfOp the single column of the table?
//
VarRefOp varRefOp = n.Child1.Child0.Op as VarRefOp;
if (varRefOp == null || varRefOp.Var != scanTableOp.Table.Columns[0])
{
return false;
}
//
// All conditions match. Return the info from the IsOf predicate
//
typeFilter = isOfOp;
return true;
}
/// <summary>
/// Handler for a FilterOp. Usually delegates to VisitRelOpDefault.
///
/// There's one special case - where we have an ISOF predicate over a ScanTable. In that case, we attempt
/// to get a more "optimal" view; and return that optimal view
///
/// </summary>
/// <param name="op">the filterOp</param>
/// <param name="n">the node tree</param>
/// <returns></returns>
public override Node Visit(FilterOp op, Node n)
{
IsOfOp typeFilter;
if (IsOfTypeOverScanTable(n, out typeFilter))
{
Node ret = ProcessScanTable(n.Child0, (ScanTableOp)n.Child0.Op, ref typeFilter);
if (typeFilter != null)
{
n.Child1 = VisitNode(n.Child1);
n.Child0 = ret;
ret = n;
}
return ret;
}
else
{
return VisitRelOpDefault(op, n);
}
}
/// <summary>
/// Visit a ProjectOp; if the input is a SortOp, we pullup the sort over
/// the ProjectOp to ensure that we don't have nested sorts;
/// Note: This transformation cannot be moved in the normalizer,
/// because it needs to happen before any subquery augmentation happens.
/// </summary>
/// <param name="op"></param>
/// <param name="n"></param>
/// <returns></returns>
public override Node Visit(ProjectOp op, Node n)
{
PlanCompiler.Assert(n.HasChild0, "projectOp without input?");
if (OpType.Sort == n.Child0.Op.OpType || OpType.ConstrainedSort == n.Child0.Op.OpType)
{
SortBaseOp sort = (SortBaseOp)n.Child0.Op;
// Don't pullup the sort if it doesn't have any keys.
// An example of such sort is "ctx.Products.Take(1)".
if (sort.Keys.Count > 0)
{
IList<Node> sortChildren = new List<Node>();
sortChildren.Add(n);
//A ConstrainedSort has two other children besides the input and it needs to keep them.
for (int i = 1; i < n.Child0.Children.Count; i++)
{
sortChildren.Add(n.Child0.Children[i]);
}
// Replace the ProjectOp input (currently the Sort node) with the input to the Sort.
n.Child0 = n.Child0.Child0;
// Vars produced by the Sort input and used as SortKeys should be considered outputs
// of the ProjectOp that now operates over what was the Sort input.
foreach (SortKey key in sort.Keys)
{
op.Outputs.Set(key.Var);
}
// Finally, pull the Sort over the Project by creating a new Sort node with the original
// Sort as its Op and the Project node as its only child. This is sufficient because
// the ITreeGenerator ensures that the SortOp does not have any local VarDefs.
return VisitNode(m_command.CreateNode(sort, sortChildren));
}
}
// perform default processing
Node newNode = VisitRelOpDefault(op, n);
return newNode;
}
/// <summary>
/// Mark AggregatePushdown as needed
/// </summary>
/// <param name="op">the groupByInto op</param>
/// <param name="n">the node tree</param>
/// <returns></returns>
public override Node Visit(GroupByIntoOp op, Node n)
{
this.m_compilerState.MarkPhaseAsNeeded(PlanCompilerPhase.AggregatePushdown);
return base.Visit(op, n);
}
#endregion
#endregion
#endregion
}
/// <summary>
/// Finds the record (Row) types that we're projecting out of the query, and
/// ensures that we mark them as needing a nullable sentinel, so when we
/// flatten them later we'll have one added.
/// </summary>
internal class StructuredTypeNullabilityAnalyzer : ColumnMapVisitor<HashSet<string>>
{
static internal StructuredTypeNullabilityAnalyzer Instance = new StructuredTypeNullabilityAnalyzer();
/// <summary>
/// VarRefColumnMap
/// </summary>
/// <param name="columnMap"></param>
/// <param name="typesNeedingNullSentinel"></param>
/// <returns></returns>
internal override void Visit(VarRefColumnMap columnMap, HashSet<string> typesNeedingNullSentinel)
{
AddTypeNeedingNullSentinel(typesNeedingNullSentinel, columnMap.Type);
base.Visit(columnMap, typesNeedingNullSentinel);
}
/// <summary>
/// Recursively add any Row types to the list of types needing a sentinel.
/// </summary>
/// <param name="typesNeedingNullableSentinel"></param>
/// <param name="typeUsage"></param>
private static void AddTypeNeedingNullSentinel(HashSet<string> typesNeedingNullSentinel, TypeUsage typeUsage)
{
if (TypeSemantics.IsCollectionType(typeUsage))
{
AddTypeNeedingNullSentinel(typesNeedingNullSentinel, TypeHelpers.GetElementTypeUsage(typeUsage));
}
else
{
if (TypeSemantics.IsRowType(typeUsage) || TypeSemantics.IsComplexType(typeUsage))
{
MarkAsNeedingNullSentinel(typesNeedingNullSentinel, typeUsage);
}
foreach (EdmMember m in TypeHelpers.GetAllStructuralMembers(typeUsage))
{
AddTypeNeedingNullSentinel(typesNeedingNullSentinel, m.TypeUsage);
}
}
}
/// <summary>
/// Marks the given typeUsage as needing a null sentinel.
/// Call this method instead of calling Add over the HashSet directly, to ensure consistency.
/// </summary>
/// <param name="typesNeedingNullSentinel"></param>
/// <param name="typeUsage"></param>
internal static void MarkAsNeedingNullSentinel(HashSet<string> typesNeedingNullSentinel, TypeUsage typeUsage)
{
typesNeedingNullSentinel.Add(typeUsage.EdmType.Identity);
}
}
}
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