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POEntity Framework how do I INSERT unique value on many to many relationship without having to do manual check
 

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  1. POEntity Framework how do I INSERT unique value on many to many relationship without having to do manual check
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    <p>Does anyone know how to insert unique values without explicitly having to check for an existing value?</p> <p>I am able to make this work, but I am less than impressed with the code I had to write. Basically I created a helper function to check a unique value on my container.</p> <p>The structure is pretty basic.</p> <p>[ Entry ] *&lt;----->* [ UniqueValue ]</p> <p><strong>Main code</strong></p> <pre><code>public static void ImportStuff () { //Generate a list of importable items List&lt;DtoItems&gt; items = DtoItemGetter.GetItems(); using( var container = new MyEntities() ) { foreach( var item in items ) { Entry newEntry = CreateNewEntry( item ); //******** // Here's the call to my helper method to check // for the uniqueness of the values on the item I am importing //******** item.UniqueValuesList.ForEach( uv =&gt; HelperMethod( container, newEntry, uv ) ); containter.AddToEntries( newEntry ); //Less important... but it would be nice if I didn't // have to save everytime I add an new entry... but // this necessary for the Helper check. container.SaveChanges(); } } } </code></pre> <p><strong>Helper Method</strong></p> <pre><code>public static void HelperMethod( MyEntities container, Entry newEntry, string checkValue ) { UniqueItem unique = null; //Have to check to see if it already exists in the DB container.uniqueItems.ForEach( uv =&gt; { if( uv.Name == checkValue ) { unique = uv; } } ); //Here's the money, either add the one I found, or //create a new one... meh newEntry.UniqueItems.Add( unique ?? new UniqueItem { Name = checkValue } ); } </code></pre> <p>Hopefully this makes enough sense.</p>
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    1. USNicholas
    1. USNicholas
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    1. COWhy do you keep checking after you already found a match?
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      1. POEntity Framework how do I INSERT unique value on many to many relationship without having to do manual check
      1. USpaparazzo
    2. COThat is pretty bad code. It queries all uniqueItems in loop. If you want to add 100 items you will move all records from uniqeItems in database to your application 100 times - and that is only for single foreach but you have two nested loops + iteration of all retrieved items.
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      1. USLadislav Mrnka
    3. COLet's clarify that performance is not an issue. This is a controlled one-time import step... so who cares if it's resource intensive. I'm not trying to save virtual trees. The point of my question is to avoid the manual check on the unique items in the DB. I'm looking for some EF auto-magic. Anyway, I see below that @raptorious understands my question.
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      1. POEntity Framework how do I INSERT unique value on many to many relationship without having to do manual check
      1. USNicholas
 

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