/// <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;
}
}
}
private void CheckClearedEntryOnSpan(
object targetValue, IEntityWrapper wrappedSource, EntityKey sourceKey, AssociationEndMember targetMember)
{
// If a relationship does not exist on the server but does exist on the client,
// we may need to remove it, depending on the current state and the MergeOption
if ((null != (object)sourceKey) &&
(null == targetValue) &&
(MergeOption == MergeOption.PreserveChanges ||
MergeOption == MergeOption.OverwriteChanges))
{
// When the spanned value is null, it may be because the spanned association applies to a
// subtype of the entity's type, and the entity is not actually an instance of that type.
var sourceEnd = MetadataHelper.GetOtherAssociationEnd(targetMember);
EdmType expectedSourceType = ((RefType)sourceEnd.TypeUsage.EdmType).ElementType;
TypeUsage entityTypeUsage;
if (!Context.Perspective.TryGetType(wrappedSource.IdentityType, out entityTypeUsage) ||
entityTypeUsage.EdmType.EdmEquals(expectedSourceType) ||
TypeSemantics.IsSubTypeOf(entityTypeUsage.EdmType, expectedSourceType))
{
// Otherwise, the source entity is the correct type (exactly or a subtype) for the source
// end of the spanned association, so validate that the relationhip that was spanned is
// part of the Container owning the EntitySet of the root entity.
// This can be done by comparing the EntitySet of the row's entity to the relationships
// in the Container and their AssociationSetEnd's type
CheckClearedEntryOnSpan(sourceKey, targetMember);
}
}
}
internal DbRelatedEntityRef(
RelationshipEndMember sourceEnd,
RelationshipEndMember targetEnd,
DbExpression targetEntityRef)
{
if (!object.ReferenceEquals((object)sourceEnd.DeclaringType, (object)targetEnd.DeclaringType))
{
throw new ArgumentException(Strings.Cqt_RelatedEntityRef_TargetEndFromDifferentRelationship, nameof(targetEnd));
}
if (object.ReferenceEquals((object)sourceEnd, (object)targetEnd))
{
throw new ArgumentException(Strings.Cqt_RelatedEntityRef_TargetEndSameAsSourceEnd, nameof(targetEnd));
}
if (targetEnd.RelationshipMultiplicity != RelationshipMultiplicity.One && targetEnd.RelationshipMultiplicity != RelationshipMultiplicity.ZeroOrOne)
{
throw new ArgumentException(Strings.Cqt_RelatedEntityRef_TargetEndMustBeAtMostOne, nameof(targetEnd));
}
if (!TypeSemantics.IsReferenceType(targetEntityRef.ResultType))
{
throw new ArgumentException(Strings.Cqt_RelatedEntityRef_TargetEntityNotRef, nameof(targetEntityRef));
}
EntityTypeBase elementType1 = TypeHelpers.GetEdmType <RefType>(targetEnd.TypeUsage).ElementType;
EntityTypeBase elementType2 = TypeHelpers.GetEdmType <RefType>(targetEntityRef.ResultType).ElementType;
if (!elementType1.EdmEquals((MetadataItem)elementType2) && !TypeSemantics.IsSubTypeOf((EdmType)elementType2, (EdmType)elementType1))
{
throw new ArgumentException(Strings.Cqt_RelatedEntityRef_TargetEntityNotCompatible, nameof(targetEntityRef));
}
this._targetEntityRef = targetEntityRef;
this._targetEnd = targetEnd;
this._sourceEnd = sourceEnd;
}
internal DbRelatedEntityRef(RelationshipEndMember sourceEnd, RelationshipEndMember targetEnd, DbExpression targetEntityRef)
{
// Validate that the specified relationship ends are:
// 1. Non-null
// 2. From the same metadata workspace as that used by the command tree
DebugCheck.NotNull(sourceEnd);
DebugCheck.NotNull(targetEnd);
// Validate that the specified target entity ref is:
// 1. Non-null
DebugCheck.NotNull(targetEntityRef);
// Validate that the specified source and target ends are:
// 1. Declared by the same relationship type
if (!ReferenceEquals(sourceEnd.DeclaringType, targetEnd.DeclaringType))
{
throw new ArgumentException(Strings.Cqt_RelatedEntityRef_TargetEndFromDifferentRelationship, "targetEnd");
}
// 2. Not the same end
if (ReferenceEquals(sourceEnd, targetEnd))
{
throw new ArgumentException(Strings.Cqt_RelatedEntityRef_TargetEndSameAsSourceEnd, "targetEnd");
}
// Validate that the specified target end has multiplicity of at most one
if (targetEnd.RelationshipMultiplicity != RelationshipMultiplicity.One
&&
targetEnd.RelationshipMultiplicity != RelationshipMultiplicity.ZeroOrOne)
{
throw new ArgumentException(Strings.Cqt_RelatedEntityRef_TargetEndMustBeAtMostOne, "targetEnd");
}
// Validate that the specified target entity ref actually has a ref result type
if (!TypeSemantics.IsReferenceType(targetEntityRef.ResultType))
{
throw new ArgumentException(Strings.Cqt_RelatedEntityRef_TargetEntityNotRef, "targetEntityRef");
}
// Validate that the specified target entity is of a type that can be reached by navigating to the specified relationship end
var endType = TypeHelpers.GetEdmType <RefType>(targetEnd.TypeUsage).ElementType;
var targetType = TypeHelpers.GetEdmType <RefType>(targetEntityRef.ResultType).ElementType;
if (!endType.EdmEquals(targetType) &&
!TypeSemantics.IsSubTypeOf(targetType, endType))
{
throw new ArgumentException(Strings.Cqt_RelatedEntityRef_TargetEntityNotCompatible, "targetEntityRef");
}
// Validation succeeded, initialize state
_targetEntityRef = targetEntityRef;
_targetEnd = targetEnd;
_sourceEnd = sourceEnd;
}
// <summary>
// Determines whether the specified { from, to } relationship end pairing represents a navigation that is
// valid for a relationship span sourced by an instance of the specified entity type.
// </summary>
// <param name="compareType"> The Entity type which valid 'from' ends must reference (or a supertype of that Entity type) </param>
// <param name="associationType"> The Association type to consider. </param>
// <param name="fromEnd"> The candidate 'from' end, which will be checked based on the Entity type it references </param>
// <param name="toEnd"> The candidate 'to' end, which will be checked base on the upper bound of its multiplicity </param>
// <returns>
// <c>True</c> if the end pairing represents a valid navigation from an instance of the specified entity type to an association end with a multiplicity upper bound of at most 1; otherwise <c>false</c>
// </returns>
private static bool IsValidRelationshipSpan(
EntityType compareType, AssociationType associationType, AssociationEndMember fromEnd, AssociationEndMember toEnd)
{
// Only a relationship end with a multiplicity of AT MOST one may be
// considered as the 'to' end, so that the cardinality of the result
// of the relationship span has an upper bound of 1.
// Therefore ends with RelationshipMultiplicity of EITHER One OR ZeroOrOne
// are the only ends that should be considered as target ends.
// Note that a relationship span can be sourced by an Entity that is of the same type
// as the Entity type referenced by the 'from' end OR any type in the same branch of
// the type hierarchy.
//
// For example, in the following hierarchy:
//
// A (*<-->?) AOwner
// |_B (*<-->1) BOwner
// |_A1 (*<-->?) A1Owner
// |_A2
// |_A3_1 (1<-->?) A3_1Owner
// |_A3_2 (*<-->1) A3_2Owner
//
// An instance of 'A' would need ALL the 'AOwner', 'BOwner', 'A1Owner', 'A3_1Owner' and 'A3_2Owner' ends
// spanned in because an instance of 'A' could actually be an instance of A, B, A1, A2, A3_1 or A3_2.
// An instance of 'B' would only need 'AOwner' and 'BOwner' spanned in.
// An instance of A2 would need 'AOwner', 'A1Owner', 'A3_1Owner' and 'A3_2Owner' spanned in.
// An instance of A3_1 would only need 'AOwner', 'A1Owner' and 'A3_1Owner' spanned in.
//
// In general, the rule for relationship span is:
// - 'To' end cardinality AT MOST one
// AND
// - Referenced Entity type of 'From' end is equal to instance Entity type
// OR
// - Referenced Entity type of 'From' end is a supertype of instance Entity type
// OR
// - Referenced Entity type of 'From' end is a subtype of instance Entity type
// (this follows from the fact that an instance of 'A' may be an instance of any of its derived types.
// Navigation for a subtype relationship will return null if the Entity instance navigation source
// is not actually of the required subtype).
//
if (!associationType.IsForeignKey
&&
(RelationshipMultiplicity.One == toEnd.RelationshipMultiplicity ||
RelationshipMultiplicity.ZeroOrOne == toEnd.RelationshipMultiplicity))
{
var fromEntityType = (EntityType)((RefType)fromEnd.TypeUsage.EdmType).ElementType;
return(EntityTypeEquals(compareType, fromEntityType) ||
TypeSemantics.IsSubTypeOf(compareType, fromEntityType) ||
TypeSemantics.IsSubTypeOf(fromEntityType, compareType));
}
return(false);
}
private static bool IsValidRelationshipSpan(
EntityType compareType,
AssociationType associationType,
AssociationEndMember fromEnd,
AssociationEndMember toEnd)
{
if (associationType.IsForeignKey || RelationshipMultiplicity.One != toEnd.RelationshipMultiplicity && toEnd.RelationshipMultiplicity != RelationshipMultiplicity.ZeroOrOne)
{
return(false);
}
EntityType elementType = (EntityType)((RefType)fromEnd.TypeUsage.EdmType).ElementType;
if (!ObjectSpanRewriter.EntityTypeEquals((EntityTypeBase)compareType, (EntityTypeBase)elementType) && !TypeSemantics.IsSubTypeOf((EdmType)compareType, (EdmType)elementType))
{
return(TypeSemantics.IsSubTypeOf((EdmType)elementType, (EdmType)compareType));
}
return(true);
}
internal void Merge(
EntityTypeBase neededRootEntityType,
bool includesSubtypes,
ExplicitDiscriminatorMap discriminatorMap)
{
if (this.RootEntityType == neededRootEntityType && this.IncludesSubTypes == includesSubtypes)
{
return;
}
if (!this.IncludesSubTypes || !includesSubtypes)
{
this.DiscriminatorMap = (ExplicitDiscriminatorMap)null;
}
if (TypeSemantics.IsSubTypeOf((EdmType)this.RootEntityType, (EdmType)neededRootEntityType))
{
this.RootEntityType = neededRootEntityType;
this.DiscriminatorMap = discriminatorMap;
}
if (TypeSemantics.IsSubTypeOf((EdmType)neededRootEntityType, (EdmType)this.RootEntityType))
{
return;
}
this.DiscriminatorMap = (ExplicitDiscriminatorMap)null;
}
private void CheckClearedEntryOnSpan(
object targetValue,
IEntityWrapper wrappedSource,
EntityKey sourceKey,
AssociationEndMember targetMember)
{
if ((object)sourceKey == null || targetValue != null || this.MergeOption != MergeOption.PreserveChanges && this.MergeOption != MergeOption.OverwriteChanges)
{
return;
}
EdmType elementType = (EdmType)((RefType)MetadataHelper.GetOtherAssociationEnd(targetMember).TypeUsage.EdmType).ElementType;
TypeUsage outTypeUsage;
if (this.Context.Perspective.TryGetType(wrappedSource.IdentityType, out outTypeUsage) && !outTypeUsage.EdmType.EdmEquals((MetadataItem)elementType) && !TypeSemantics.IsSubTypeOf(outTypeUsage.EdmType, elementType))
{
return;
}
this.CheckClearedEntryOnSpan(sourceKey, targetMember);
}