public static bool FkeyHasChanged(SchemaChanges changes, SubObjectState <FkeyType, FkeyType.State> current)
{
if (current == null)
{
return(true);
}
var desired = changes.Desired.Get(current);
// The foreign key doesn't exist in the desired schema at all
if (desired == null)
{
return(true);
}
// The destination table has changed
if (desired.State.ToTable != current.State.ToTable)
{
return(true);
}
// Either the from or to table might need to be dropped entirely to reorder fields
if (FieldType.IsFieldReorderPossiblyNeeded(changes, current.ParentIdentifier) ||
FieldType.IsFieldReorderPossiblyNeeded(changes, current.State.ToTable))
{
return(true);
}
// It's changed from cascading to not or vice versa
if (desired.State.IsCascadeDelete != current.State.IsCascadeDelete)
{
return(true);
}
// The sequence of field name pairs don't match
if (!Enumerable.SequenceEqual(desired.State.Joins, current.State.Joins, FieldPair.GetComparer(changes.DbDriver)))
{
return(true);
}
// Any of the fields in either table are changing
if (current.State.Joins.Any(field =>
FieldType.FieldHasChanged(changes, current.ParentIdentifier, FieldType.Identifier(field.FromFieldName)) ||
FieldType.FieldHasChanged(changes, current.State.ToTable, FieldType.Identifier(field.ToFieldName))))
{
return(true);
}
// The unique index on the destination table that corresponds to the destination fields is changing
var ukey = UniqueIndexType.ChildrenFrom(changes.Current, current.State.ToTable)
.SingleOrDefault(key => new HashSet <Identifier>(key.State.IndexState.Fields).SetEquals(from field in current.State.Joins
select FieldType.Identifier(field.ToFieldName)));
if (ukey != null && UniqueIndexType.IndexHasChanged(changes, ukey))
{
return(true);
}
return(false);
}