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POMS SQL Server 2008 Check Constraint, and LINQ-To-SQL
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  1. POMS SQL Server 2008 Check Constraint, and LINQ-To-SQL
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    copied!<p>This is a tough question to word...so bear with me.</p> <p>I have two tables in my database, <code>[Item]</code> and <code>[AssignedProperty]</code>. <code>[AssignedProperty]</code> is the child in a parent-child relationship with <code>[Item]</code>. So it basically just has an ItemID field and a foreign key relationship utilizing it. <code>[AssignedProperty]</code> also has an identical relationship with another table named <code>[Property]</code>, and its own primary key, AssignedPropertyID. This creates a nice many-to-many relationship. I have a constraint however, that dictates that one <code>[AssignedProperty]</code> cannot have duplicate occurrences of ItemID and PropertyID in the same record. Therefore an <code>[Item]</code> can only have one of each <code>[Property]</code>.</p> <p>This works nicely, but with LINQ-To-SQL, theres an issue in what I think is the order of execution that conflicts with this constraint.</p> <p>To produce this error, I load up an <code>[Item]</code> in my application using LINQ-To-SQL. I then select an [<code>AssignedProperty]</code> object, from the item's <code>[AssignedProperties]</code> collection and delete it. I then create a new <code>[AssignedProperty]</code> object with the exact same ItemID and PropertyID as the one I just deleted, and add it back to the collection. When I call <code>[SubmitChanges]</code> on the DataContext, it will flag me on the constraint. If the old <code>[AssignedProperty]</code> record was deleted first, then there is no reason why the new one should produce that error. It looks like it's attempting to insert the new <code>[AssignedProperty]</code> before deleting the old one.</p> <p>How should I fix this, and in the database or my app? TIA</p>
 

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