/// <summary>
/// Returns a unique association name for the specified MetaAssociation
/// </summary>
/// <param name="metaAssociation">A <see cref="MetaAssociation"/>.</param>
/// <returns>A <see cref="String"/> containing the association name.</returns>
private string GetAssociationName(MetaAssociation metaAssociation)
{
lock (this._associationNameMap)
{
// We need a unique key for this association, so we use the MetaAssociation
// itself. In the case of bi-directional associations, we use the FK side.
if (!metaAssociation.IsForeignKey && metaAssociation.OtherMember != null)
{
metaAssociation = metaAssociation.OtherMember.Association;
}
string associationName = null;
if (!this._associationNameMap.TryGetValue(metaAssociation, out associationName))
{
// names are always formatted non-FK side type name followed by FK side type name
// For example, the name for both ends of the PurchaseOrder/PurchaseOrderDetail
// association will be PurchaseOrder_PurchaseOrderDetail
if (metaAssociation.IsForeignKey)
{
associationName = string.Format(CultureInfo.InvariantCulture, "{0}_{1}", metaAssociation.OtherType.Name, metaAssociation.ThisMember.DeclaringType.Name);
}
else
{
associationName = string.Format(CultureInfo.InvariantCulture, "{0}_{1}", metaAssociation.ThisMember.DeclaringType.Name, metaAssociation.OtherType.Name);
}
associationName = TypeDescriptionContextBase.MakeUniqueName(associationName, this._associationNameMap.Values);
this._associationNameMap[metaAssociation] = associationName;
}
return associationName;
}
}
private void SetAssociationKeyInfo(MetaAssociation association) {
DLinqColumnProvider column = (DLinqColumnProvider)FromColumn;
List<string> foreignKeyNames = new List<string>();
int count = column.Member.Association.ThisKey.Count;
for (int i = 0; i < count; i++) {
MetaDataMember thisKeyMetaDataMember = column.Member.Association.ThisKey[i];
MetaDataMember otherKeyMetaDataMember = column.Member.Association.OtherKey[i];
DLinqColumnProvider thisEntityMemberComponent = FindColumn(column.Table, thisKeyMetaDataMember.Name);
if (ShouldRemoveThisAssociation(association)) {
column.ShouldRemove = true;
return;
}
foreignKeyNames.Add(thisEntityMemberComponent.Name);
if (thisEntityMemberComponent.IsPrimaryKey) {
IsPrimaryKeyInThisTable = true;
}
if (association.IsForeignKey) {
thisEntityMemberComponent.IsForeignKeyComponent = true;
}
}
ForeignKeyNames = new ReadOnlyCollection<string>(foreignKeyNames);
}
private void SetOtherEndOfAssociation(MetaAssociation association) {
DLinqTableProvider entityMemberParentEntity = (DLinqTableProvider)FromColumn.Table;
DLinqDataModelProvider parentEntityDataContext = (DLinqDataModelProvider)entityMemberParentEntity.DataModel;
if (association.OtherMember != null) {
ToColumn = parentEntityDataContext.ColumnLookup[(PropertyInfo)association.OtherMember.Member];
} else {
ToTable = ((DLinqDataModelProvider)FromColumn.Table.DataModel).DLinqTables.Single(tp => tp.EntityType == association.OtherType.Type);
}
}
internal void Add(MetaAssociation assoc, TrackedObject from, TrackedObject to)
{
Dictionary<TrackedObject, TrackedObject> pairs;
if(!associations.TryGetValue(assoc, out pairs))
{
pairs = new Dictionary<TrackedObject, TrackedObject>();
associations.Add(assoc, pairs);
}
pairs.Add(from, to);
}
internal RelationComposer(ParameterExpression parameter, MetaAssociation association, Expression otherSouce, Expression parameterReplacement) {
if (parameter==null)
throw Error.ArgumentNull("parameter");
if (association == null)
throw Error.ArgumentNull("association");
if (otherSouce == null)
throw Error.ArgumentNull("otherSouce");
if (parameterReplacement==null)
throw Error.ArgumentNull("parameterReplacement");
this.parameter = parameter;
this.association = association;
this.otherSouce = otherSouce;
this.parameterReplacement = parameterReplacement;
}
internal TrackedObject this[MetaAssociation assoc, TrackedObject from]
{
get
{
Dictionary<TrackedObject, TrackedObject> pairs;
if(associations.TryGetValue(assoc, out pairs))
{
TrackedObject to;
if(pairs.TryGetValue(from, out to))
{
return to;
}
}
return null;
}
}
private bool ShouldRemoveThisAssociation(MetaAssociation association) {
if (Direction == AssociationDirection.ManyToOne && !association.OtherKeyIsPrimaryKey) {
return true;
}
if (Direction == AssociationDirection.OneToMany && !association.ThisKeyIsPrimaryKey) {
return true;
}
if (Direction == AssociationDirection.OneToOne) {
if (!association.IsForeignKey && !association.ThisKeyIsPrimaryKey) {
return true;
}
if (association.IsForeignKey && !association.OtherKeyIsPrimaryKey) {
return true;
}
}
return false;
}
private bool HasAssociationChanged(MetaAssociation assoc, TrackedObject item) {
if (item.Original != null && item.Current != null) {
if (assoc.ThisMember.StorageAccessor.HasAssignedValue(item.Current) ||
assoc.ThisMember.StorageAccessor.HasLoadedValue(item.Current)
) {
return this.GetOtherItem(assoc, item.Current) != this.GetOtherItem(assoc, item.Original);
}
else {
object[] currentFKs = CommonDataServices.GetForeignKeyValues(assoc, item.Current);
object[] originaFKs = CommonDataServices.GetForeignKeyValues(assoc, item.Original);
for (int i = 0, n = currentFKs.Length; i < n; i++) {
if (!object.Equals(currentFKs[i], originaFKs[i]))
return true;
}
}
}
return false;
}
private TrackedObject GetOtherItem(MetaAssociation assoc, object instance) {
if (instance == null)
return null;
object other = null;
// Don't load unloaded references
if (assoc.ThisMember.StorageAccessor.HasAssignedValue(instance) ||
assoc.ThisMember.StorageAccessor.HasLoadedValue(instance)
) {
other = assoc.ThisMember.MemberAccessor.GetBoxedValue(instance);
}
else if (assoc.OtherKeyIsPrimaryKey) {
// Maybe it's in the cache, but not yet attached through reference.
object[] foreignKeys = CommonDataServices.GetForeignKeyValues(assoc, instance);
other = this.services.GetCachedObject(assoc.OtherType, foreignKeys);
}
// else the other key is not the primary key so there is no way to try to look it up
return (other != null) ? this.tracker.GetTrackedObject(other) : null;
}
// Ensure the the member and foreign keys are nulled so that after trackedInstance is deleted,
// the object does not appear to be associated with the other side anymore. This prevents the deleted object
// from referencing objects still in the cache, but also will prevent the related object from being implicitly loaded
private static void ClearForeignKeysHelper(MetaAssociation assoc, object trackedInstance) {
Debug.Assert(assoc.IsForeignKey, "Foreign key clearing should only happen on foreign key side of the association.");
Debug.Assert(assoc.ThisMember.IsAssociation, "Expected ThisMember of an association to always be an association.");
// If this member is one of our deferred loaders, and it does not already have a value, explicitly set the deferred source to
// null so that when we set the association member itself to null later, it doesn't trigger an implicit load.
// This is only necessary if the value has not already been assigned or set, because otherwise we won't implicitly load anyway when the member is accessed.
MetaDataMember thisMember = assoc.ThisMember;
if (thisMember.IsDeferred &&
!(thisMember.StorageAccessor.HasAssignedValue(trackedInstance) || thisMember.StorageAccessor.HasLoadedValue(trackedInstance)))
{
// If this is a deferred member, set the value directly in the deferred accessor instead of going
// through the normal member accessor, so that we don't trigger an implicit load.
thisMember.DeferredSourceAccessor.SetBoxedValue(ref trackedInstance, null);
}
// Notify the object that the relationship should be considered deleted.
// This allows the object to do its own fixup even when we can't do it automatically.
thisMember.MemberAccessor.SetBoxedValue(ref trackedInstance, null);
// Also set the foreign key values to null if possible
for (int i = 0, n = assoc.ThisKey.Count; i < n; i++) {
MetaDataMember thisKey = assoc.ThisKey[i];
if (thisKey.CanBeNull) {
thisKey.StorageAccessor.SetBoxedValue(ref trackedInstance, null);
}
}
}
public void SetAssociation(MetaAssociation association)
{
metaAssociation = association;
}
/// <summary>
/// Create an Expression representing the given association and key value expressions.
/// </summary>
internal static Expression TranslateAssociation(DataContext context, MetaAssociation association, Expression otherSource, Expression[] keyValues, Expression thisInstance) {
if (association == null)
throw Error.ArgumentNull("association");
if (keyValues == null)
throw Error.ArgumentNull("keyValues");
if (context.LoadOptions!=null) {
LambdaExpression subquery = context.LoadOptions.GetAssociationSubquery(association.ThisMember.Member);
if (subquery!=null) {
RelationComposer rc = new RelationComposer(subquery.Parameters[0], association, otherSource, thisInstance);
return rc.Visit(subquery.Body);
}
}
return WhereClauseFromSourceAndKeys(otherSource, association.OtherKey.ToArray(), keyValues);
}
private void SetDirection(MetaAssociation association) {
if (association.IsMany) {
Direction = AssociationDirection.OneToMany;
} else if (association.OtherMember == null || association.OtherMember.Association.IsMany) {
// there might not be the other member if this is a one-sided association
Direction = AssociationDirection.ManyToOne;
} else {
Direction = AssociationDirection.OneToOne;
}
}
