/// <summary>
/// Retrieves the dependent end of this association, given the following rules in order of priority:
/// 1. If there is a referential constraint defined on the association, this returns the DependentEnd.
/// 2. If the association's multiplicity is 1:1 and OnDelete='Cascade' is defined on the first end, then this returns the second end.
/// If OnDelete='Cascade' is not defined on the first end, this returns the first end.
/// 3. In a 1:* or 0..1:* association, this returns the end with the * multiplicity.
/// 4. In a 0..1:1 association, this returns the end with the 0..1 multiplicity.
/// </summary>
/// <param name="association">The association.</param>
/// <returns>The dependent end.</returns>
/// <exception cref="InvalidOperationException">if this association is *:*</exception>
public static AssociationEndMember GetDependentEnd(this AssociationType association)
{
Debug.Assert(false == association.IsManyToMany(), Resources.ErrorGetDependentEndOnManyToMany);
if (association.IsManyToMany())
{
throw new InvalidOperationException(Resources.ErrorGetDependentEndOnManyToMany);
}
if (association.ReferentialConstraints.Count > 0)
{
return(association.ReferentialConstraints.FirstOrDefault().ToRole as AssociationEndMember);
}
else
{
// Dependency is implied by OnDelete in 1:1 associations
if (association.GetEnd1().RelationshipMultiplicity == RelationshipMultiplicity.One &&
association.GetEnd2().RelationshipMultiplicity == RelationshipMultiplicity.One)
{
return(association.GetEnd1().GetOnDelete() == OperationAction.Cascade ? association.GetEnd2() : association.GetEnd1());
}
// Dependency can also be implied by the multiplicity of the association
if ((association.GetEnd1().RelationshipMultiplicity == RelationshipMultiplicity.Many)
||
(association.GetEnd1().RelationshipMultiplicity == RelationshipMultiplicity.ZeroOrOne &&
association.GetEnd2().RelationshipMultiplicity == RelationshipMultiplicity.One))
{
return(association.GetEnd1());
}
return(association.GetEnd2());
}
}
/// <summary>
/// Determines if an association is across solely primary keys
/// </summary>
/// <param name="association">The association.</param>
/// <returns>true if the multiplicity of the association is 1:1, 1:0..1, or 0..1:0..1, and false otherwise</returns>
public static bool IsPKToPK(this AssociationType association)
{
if ((association.GetEnd1().RelationshipMultiplicity == RelationshipMultiplicity.One ||
association.GetEnd1().RelationshipMultiplicity == RelationshipMultiplicity.ZeroOrOne)
&&
(association.GetEnd2().RelationshipMultiplicity == RelationshipMultiplicity.One ||
association.GetEnd2().RelationshipMultiplicity == RelationshipMultiplicity.ZeroOrOne))
{
return(true);
}
return(false);
}
private static bool IsAssociatedWithEntityType(this AssociationType association, EntityType entityType)
{
var end1 = association.GetEnd1();
AssociationEndMember end2 = association.GetEnd2();
return(end1.GetEntityType() == entityType || end2.GetEntityType() == entityType);
}
/// <summary>
/// Given an AssociationEndMember of this Association, this method will return the other end participating
/// in the association
/// </summary>
/// <param name="association">The Association.</param>
/// <param name="end">An AssociationEndMember.</param>
/// <returns>The other end.</returns>
public static AssociationEndMember GetOtherEnd(this AssociationType association, AssociationEndMember end)
{
if (end != null)
{
return(end == association.GetEnd1() ? association.GetEnd2() : association.GetEnd1());
}
return(null);
}
/// <summary>
/// Determines if an association's multiplicity is *:*
/// </summary>
/// <param name="association">The association.</param>
/// <returns>true if association's multiplicity is *:*, false otherwise</returns>
public static bool IsManyToMany(this AssociationType association)
{
return(association.GetEnd1().RelationshipMultiplicity == RelationshipMultiplicity.Many &&
association.GetEnd2().RelationshipMultiplicity == RelationshipMultiplicity.Many);
}
