|
//---------------------------------------------------------------------
// <copyright file="ViewgenContext.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//
// @owner Microsoft
// @backupOwner Microsoft
//---------------------------------------------------------------------
namespace System.Data.Mapping.ViewGeneration
{
using System.Collections.Generic;
using System.Data.Common.Utils;
using System.Data.Entity;
using System.Data.Mapping.ViewGeneration.QueryRewriting;
using System.Data.Mapping.ViewGeneration.Structures;
using System.Data.Mapping.ViewGeneration.Utils;
using System.Data.Metadata.Edm;
using System.Diagnostics;
using System.Linq;
using System.Text;
internal class ViewgenContext : InternalBase
{
#region Fields
private ConfigViewGenerator m_config;
private ViewTarget m_viewTarget;
// Extent for which the view is being generated
private EntitySetBase m_extent;
// Different maps for members
private MemberMaps m_memberMaps;
private EdmItemCollection m_edmItemCollection;
private StorageEntityContainerMapping m_entityContainerMapping;
// The normalized cells that are created
private List<LeftCellWrapper> m_cellWrappers;
// Implicit constraints between members in queries based on schema. E.g., p.Addr IS NOT NULL <=> p IS OF Customer
private FragmentQueryProcessor m_leftFragmentQP;
// In addition to constraints for each right extent contains constraints due to associations
private FragmentQueryProcessor m_rightFragmentQP;
private CqlIdentifiers m_identifiers;
// Maps (left) queries to their rewritings in terms of views
private Dictionary<FragmentQuery, Tile<FragmentQuery>> m_rewritingCache;
#endregion
#region Constructors
internal ViewgenContext(ViewTarget viewTarget, EntitySetBase extent, IEnumerable<Cell> extentCells,
CqlIdentifiers identifiers, ConfigViewGenerator config, MemberDomainMap queryDomainMap,
MemberDomainMap updateDomainMap, StorageEntityContainerMapping entityContainerMapping)
{
foreach (Cell cell in extentCells)
{
Debug.Assert(extent.Equals(cell.GetLeftQuery(viewTarget).Extent));
Debug.Assert(cell.CQuery.NumProjectedSlots == cell.SQuery.NumProjectedSlots);
}
m_extent = extent;
m_viewTarget = viewTarget;
m_config = config;
m_edmItemCollection = entityContainerMapping.StorageMappingItemCollection.EdmItemCollection;
m_entityContainerMapping = entityContainerMapping;
m_identifiers = identifiers;
// create a copy of updateDomainMap so generation of query views later on is not affected
// it is modified in QueryRewriter.AdjustMemberDomainsForUpdateViews
updateDomainMap = updateDomainMap.MakeCopy();
// Create a signature generator that handles all the
// multiconstant work and generating the signatures
MemberDomainMap domainMap = viewTarget == ViewTarget.QueryView ? queryDomainMap : updateDomainMap;
m_memberMaps = new MemberMaps(viewTarget, MemberProjectionIndex.Create(extent, m_edmItemCollection), queryDomainMap, updateDomainMap);
// Create left fragment KB: includes constraints for the extent to be constructed
FragmentQueryKB leftKB = new FragmentQueryKB();
leftKB.CreateVariableConstraints(extent, domainMap, m_edmItemCollection);
m_leftFragmentQP = new FragmentQueryProcessor(leftKB);
m_rewritingCache = new Dictionary<FragmentQuery, Tile<FragmentQuery>>(
FragmentQuery.GetEqualityComparer(m_leftFragmentQP));
// Now using the signatures, create new cells such that
// "extent's" query (C or S) is described in terms of multiconstants
if (!CreateLeftCellWrappers(extentCells, viewTarget))
{
return;
}
// Create right fragment KB: includes constraints for all extents and association roles of right queries
FragmentQueryKB rightKB = new FragmentQueryKB();
MemberDomainMap rightDomainMap = viewTarget == ViewTarget.QueryView ? updateDomainMap : queryDomainMap;
foreach (LeftCellWrapper leftCellWrapper in m_cellWrappers)
{
EntitySetBase rightExtent = leftCellWrapper.RightExtent;
rightKB.CreateVariableConstraints(rightExtent, rightDomainMap, m_edmItemCollection);
rightKB.CreateAssociationConstraints(rightExtent, rightDomainMap, m_edmItemCollection);
}
if (m_viewTarget == ViewTarget.UpdateView)
{
CreateConstraintsForForeignKeyAssociationsAffectingThisWarapper(rightKB, rightDomainMap);
}
m_rightFragmentQP = new FragmentQueryProcessor(rightKB);
// Check for concurrency control tokens
if (m_viewTarget == ViewTarget.QueryView)
{
CheckConcurrencyControlTokens();
}
// For backward compatibility -
// order wrappers by increasing domain size, decreasing number of attributes
m_cellWrappers.Sort(LeftCellWrapper.Comparer);
}
/// <summary>
/// Find the Foreign Key Associations that relate EntitySets used in these left cell wrappers and
/// add any equivalence facts between sets implied by 1:1 associations.
/// We can collect other implication facts but we don't have a scenario that needs them( yet ).
/// </summary>
/// <param name="rightKB"></param>
/// <param name="rightDomainMap"></param>
private void CreateConstraintsForForeignKeyAssociationsAffectingThisWarapper(FragmentQueryKB rightKB, MemberDomainMap rightDomainMap)
{
//First find the entity types of the sets in these cell wrappers.
var entityTypes = m_cellWrappers.Select(it => it.RightExtent).OfType<EntitySet>().Select(it => it.ElementType);
//Get all the foreign key association sets in these entity sets
var allForeignKeyAssociationSets = this.m_entityContainerMapping.EdmEntityContainer.BaseEntitySets.OfType<AssociationSet>().Where(it => it.ElementType.IsForeignKey);
//Find all the foreign key associations that have corresponding sets
var oneToOneForeignKeyAssociationsForThisWrapper = allForeignKeyAssociationSets.Select(it => it.ElementType);
//Find all the 1:1 associations from the above list
oneToOneForeignKeyAssociationsForThisWrapper = oneToOneForeignKeyAssociationsForThisWrapper.Where(it => (it.AssociationEndMembers.All(endMember => endMember.RelationshipMultiplicity == RelationshipMultiplicity.One)));
//Filter the 1:1 foreign key associations to the ones relating the sets used in these cell wrappers.
oneToOneForeignKeyAssociationsForThisWrapper = oneToOneForeignKeyAssociationsForThisWrapper.Where(it => (it.AssociationEndMembers.All(endMember => entityTypes.Contains(endMember.GetEntityType()))));
//filter foreign key association sets to the sets that are 1:1 and affecting this wrapper.
var oneToOneForeignKeyAssociationSetsForThisWrapper = allForeignKeyAssociationSets.Where(it => oneToOneForeignKeyAssociationsForThisWrapper.Contains(it.ElementType));
//Collect the facts for the foreign key association sets that are 1:1 and affecting this wrapper
foreach (var assocSet in oneToOneForeignKeyAssociationSetsForThisWrapper)
{
rightKB.CreateEquivalenceConstraintForOneToOneForeignKeyAssociation(assocSet, rightDomainMap, m_edmItemCollection);
}
}
#endregion
#region Properties
internal ViewTarget ViewTarget
{
get
{
return m_viewTarget;
}
}
internal MemberMaps MemberMaps
{
get
{
return m_memberMaps;
}
}
// effects: Returns the extent for which the cells have been normalized
internal EntitySetBase Extent
{
get { return m_extent; }
}
internal ConfigViewGenerator Config
{
get { return m_config; }
}
internal CqlIdentifiers CqlIdentifiers
{
get { return m_identifiers; }
}
internal EdmItemCollection EdmItemCollection
{
get { return m_edmItemCollection; }
}
internal FragmentQueryProcessor LeftFragmentQP
{
get { return m_leftFragmentQP; }
}
internal FragmentQueryProcessor RightFragmentQP
{
get { return m_rightFragmentQP; }
}
// effects: Returns all wrappers that were originally relevant for
// this extent
internal List<LeftCellWrapper> AllWrappersForExtent
{
get
{
return m_cellWrappers;
}
}
internal StorageEntityContainerMapping EntityContainerMapping
{
get { return m_entityContainerMapping; }
}
#endregion
#region InternalMethods
// effects: Returns the cached rewriting of (left) queries in terms of views, if any
internal bool TryGetCachedRewriting(FragmentQuery query, out Tile<FragmentQuery> rewriting)
{
return m_rewritingCache.TryGetValue(query, out rewriting);
}
// effects: Records the cached rewriting of (left) queries in terms of views
internal void SetCachedRewriting(FragmentQuery query, Tile<FragmentQuery> rewriting)
{
m_rewritingCache[query] = rewriting;
}
#endregion
#region Private Methods
/// <summary>
/// Checks:
/// 1) Concurrency token is not defined in this Extent's ElementTypes' derived types
/// 2) Members with concurrency token should not have conditions specified
/// </summary>
private void CheckConcurrencyControlTokens()
{
Debug.Assert(m_viewTarget == ViewTarget.QueryView);
// Get the token fields for this extent
EntityTypeBase extentType = m_extent.ElementType;
Set<EdmMember> tokenMembers = MetadataHelper.GetConcurrencyMembersForTypeHierarchy(extentType, m_edmItemCollection);
Set<MemberPath> tokenPaths = new Set<MemberPath>(MemberPath.EqualityComparer);
foreach (EdmMember tokenMember in tokenMembers)
{
if (!tokenMember.DeclaringType.IsAssignableFrom(extentType))
{
string message = System.Data.Entity.Strings.ViewGen_Concurrency_Derived_Class(tokenMember.Name, tokenMember.DeclaringType.Name, m_extent);
ErrorLog.Record record = new ErrorLog.Record(true, ViewGenErrorCode.ConcurrencyDerivedClass, message, m_cellWrappers, String.Empty);
ExceptionHelpers.ThrowMappingException(record, m_config);
}
tokenPaths.Add(new MemberPath(m_extent, tokenMember));
}
if (tokenMembers.Count > 0)
{
foreach (LeftCellWrapper wrapper in m_cellWrappers)
{
Set<MemberPath> conditionMembers = new Set<MemberPath>(
wrapper.OnlyInputCell.CQuery.WhereClause.MemberRestrictions.Select(oneOf => oneOf.RestrictedMemberSlot.MemberPath),
MemberPath.EqualityComparer);
conditionMembers.Intersect(tokenPaths);
if (conditionMembers.Count > 0)
{
// There is a condition on concurrency tokens. Throw an exception.
StringBuilder builder = new StringBuilder();
builder.AppendLine(Strings.ViewGen_Concurrency_Invalid_Condition(MemberPath.PropertiesToUserString(conditionMembers, false), m_extent.Name));
ErrorLog.Record record = new ErrorLog.Record(true, ViewGenErrorCode.ConcurrencyTokenHasCondition, builder.ToString(), new LeftCellWrapper[] { wrapper }, String.Empty);
ExceptionHelpers.ThrowMappingException(record, m_config);
}
}
}
}
// effects: Given the cells for the extent (extentCells) along with
// the signatures (multiconstants + needed attributes) for this extent, generates
// the left cell wrappers for it extent (viewTarget indicates whether
// the view is for querying or update purposes
// Modifies m_cellWrappers to contain this list
private bool CreateLeftCellWrappers(IEnumerable<Cell> extentCells, ViewTarget viewTarget)
{
List<Cell> extentCellsList = new List<Cell>(extentCells);
List<Cell> alignedCells = AlignFields(extentCellsList, m_memberMaps.ProjectedSlotMap, viewTarget);
Debug.Assert(alignedCells.Count == extentCellsList.Count, "Cell counts disagree");
// Go through all the cells and create cell wrappers that can be used for generating the view
m_cellWrappers = new List<LeftCellWrapper>();
for (int i = 0; i < alignedCells.Count; i++)
{
Cell alignedCell = alignedCells[i];
CellQuery left = alignedCell.GetLeftQuery(viewTarget);
CellQuery right = alignedCell.GetRightQuery(viewTarget);
// Obtain the non-null projected slots into attributes
Set<MemberPath> attributes = left.GetNonNullSlots();
BoolExpression fromVariable = BoolExpression.CreateLiteral(new CellIdBoolean(m_identifiers, extentCellsList[i].CellNumber), m_memberMaps.LeftDomainMap);
FragmentQuery leftFragmentQuery = FragmentQuery.Create(fromVariable, left);
FragmentQuery rightFragmentQuery = FragmentQuery.Create(fromVariable, right);
if (viewTarget == ViewTarget.UpdateView)
{
leftFragmentQuery = m_leftFragmentQP.CreateDerivedViewBySelectingConstantAttributes(leftFragmentQuery) ?? leftFragmentQuery;
}
LeftCellWrapper leftWrapper = new LeftCellWrapper(m_viewTarget, attributes, leftFragmentQuery, left, right, m_memberMaps,
extentCellsList[i]);
m_cellWrappers.Add(leftWrapper);
}
return true;
}
// effects: Align the fields of each cell in mapping using projectedSlotMap that has a mapping
// for each member of this extent to the slot number of that member in the projected slots
// example:
// input: Proj[A,B,"5"] = Proj[F,"7",G]
// Proj[C,B] = Proj[H,I]
// output: m_projectedSlotMap: A -> 0, B -> 1, C -> 2
// Proj[A,B,null] = Proj[F,"7",null]
// Proj[null,B,C] = Proj[null,I,H]
private static List<Cell> AlignFields(IEnumerable<Cell> cells, MemberProjectionIndex projectedSlotMap,
ViewTarget viewTarget)
{
List<Cell> outputCells = new List<Cell>();
// Determine the aligned field for each cell
// The new cells have ProjectedSlotMap.Count number of fields
foreach (Cell cell in cells)
{
// If isQueryView is true, we need to consider the C side of
// the cells; otherwise, we look at the S side. Note that we
// CANNOT use cell.LeftQuery since that is determined by
// cell's isQueryView
// The query for which we are constructing the extent
CellQuery mainQuery = cell.GetLeftQuery(viewTarget);
CellQuery otherQuery = cell.GetRightQuery(viewTarget);
CellQuery newMainQuery;
CellQuery newOtherQuery;
// Create both queries where the projected slot map is used
// to determine the order of the fields of the mainquery (of
// course, the otherQuery's fields are aligned automatically)
mainQuery.CreateFieldAlignedCellQueries(otherQuery, projectedSlotMap,
out newMainQuery, out newOtherQuery);
Cell outputCell = viewTarget == ViewTarget.QueryView ?
Cell.CreateCS(newMainQuery, newOtherQuery, cell.CellLabel, cell.CellNumber) :
Cell.CreateCS(newOtherQuery, newMainQuery, cell.CellLabel, cell.CellNumber);
outputCells.Add(outputCell);
}
return outputCells;
}
#endregion
#region String Methods
internal override void ToCompactString(StringBuilder builder)
{
LeftCellWrapper.WrappersToStringBuilder(builder, m_cellWrappers, "Left Celll Wrappers");
}
#endregion
}
}
|