How to implement multi relationship in SQL Server?

Posted by Ethan on Stack Overflow See other posts from Stack Overflow or by Ethan
Published on 2010-12-27T05:50:37Z Indexed on 2010/12/27 6:54 UTC
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sql

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foreign-keys

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entity-relationship

I’m trying to design a database to use with ASP.net MVC application. Here is the scenario: There are three entities and users can post their comments for each of these different entities. I just wonder how just put one table for Comments and link all other entities to it. Obviously, Comments table needs 3 references (foreign key) to those tables but as you know these foreign keys can’t be null and just one of them can be filled for each row. Is there any better way than implementing three different tables for each entity’s comments?

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