I’m using Microsoft SQL Server 2008 Management Studio to create a relational schema by following an Entity-Relationship diagram. (included below; unrelated details removed)
entity-relationship diagram with weak entity set http://nicwaller.com/stackoverflow/er_weakentityset.png
Until now, primary and foreign keys have been working as expected. But when I try to create a foreign key from the entity relationship takes onto the weak entity set section, I get an error. Section is identified by a composite primary key in the context of course, which has course_id as a primary key. Therefore, the primary key of section is a 4-way composite key.
The entity relationship takes needs to refer to section, so it includes all 4 primary attributes from section in it’s own primary key. When trying to establish a foreign key relationship from takes to section, Studio gives the following error:
The columns in table 'section' do not match an existing primary key or UNIQUE constraint.
Am I doing something wrong, or is this an unsupported configuration? I can provide more details or the SQL schema if necessary.
The ordering of attributes in the primary and foreign key must be maintained.
(I was getting an error because the attributes of the foreign key were being specified in a different order than they occurred in the primary key.)