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Old November 10th, 2010, 01:35 PM
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Default check existence of a record in a database before inserting a new record

In my web app a user can assign muliple tags to products.
There are three tables: products, tags and products_tags to implement a many to many relationship.

My question is, how would you implement this with the Entity Framework (LINQ to Entities):
"Insert only a new tag in the tags table if it doesnt already exist there, dont add if it exists".

So before the insert i have to check first if a tag exists, whats the best way to accomplish this (best performance) ??

(Btw. The Tags table consists of TagID (PK) and TagName)

thanks for answers
Old November 15th, 2010, 03:44 AM
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In theory this is a simple matter of doing a SELECT a record with the particular values that you have and running an INSERT if it doesn't exist. However, EF is complex enough that I have steered clear to this point and don't know how to implement that in EF.

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