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//---------------------------------------------------------------------
// <copyright file="ViewCellRelation.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//
// @owner Microsoft
// @backupOwner Microsoft
//---------------------------------------------------------------------
using System.Collections.Generic;
using System.Data.Mapping.ViewGeneration.Structures;
using System.Text;
using System.Data.Common.Utils;
namespace System.Data.Mapping.ViewGeneration.Validation
{
/// <summary>
/// Represents a relation signature that lists all projected
/// slots of two cell queries in a cell after projection. So if
/// SPerson1.Disc is present in the cellquery (and part of the where
/// clause) but not in the projected slots, it is missing from a ViewCellRelation
/// </summary>
internal class ViewCellRelation : CellRelation
{
#region Constructor
// effects: Creates a view cell relation for "cell" with the
// projected slots given by slots -- cellNumber is the number of the
// cell for debugging purposes
// Also creates the BasicCellRelations for the left and right cell queries
internal ViewCellRelation(Cell cell, List<ViewCellSlot> slots, int cellNumber)
: base(cellNumber)
{
m_cell = cell;
m_slots = slots;
// We create the basiccellrelations passing this to it so that we have
// a reference from the basiccellrelations to this
m_cell.CQuery.CreateBasicCellRelation(this);
m_cell.SQuery.CreateBasicCellRelation(this);
}
#endregion
#region Fields
private Cell m_cell; // The cell for which this relation exists
private List<ViewCellSlot> m_slots; // Slots projected from both cell queries
#endregion
#region Properties
internal Cell Cell
{
get { return m_cell; }
}
#endregion
#region Methods
// requires: slot corresponds to a slot in the corresponding
// BasicCellRelation
// effects: Given a slot in the corresponding basicCellRelation,
// looks up the slot in this viewcellrelation and returns it. Returns
// null if it does not find the slot in the left or right side of the viewrelation
internal ViewCellSlot LookupViewSlot(MemberProjectedSlot slot)
{
// CHANGE_Microsoft_IMPROVE: We could have a dictionary to speed this up
foreach (ViewCellSlot viewSlot in m_slots)
{
// If the left or right slots are equal, return the viewSlot
if (ProjectedSlot.EqualityComparer.Equals(slot, viewSlot.CSlot) ||
ProjectedSlot.EqualityComparer.Equals(slot, viewSlot.SSlot))
{
return viewSlot;
}
}
return null;
}
protected override int GetHash()
{
// Note: Using CLR-Hashcode
return m_cell.GetHashCode();
// We need not hash the slots, etc - cell should give us enough
// differentiation and land the relation into the same bucket
}
internal override void ToCompactString(StringBuilder builder)
{
builder.Append("ViewRel[");
m_cell.ToCompactString(builder);
// StringUtil.ToSeparatedStringSorted(builder, m_slots, ", ");
builder.Append(']');
}
#endregion
}
}
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