Foreign key onto weak entity set in MS SQL Server 2008?
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by Nic Waller
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Published on 2010-03-18T04:22:28Z
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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)
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.
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