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POLINQ to Entities returning incorrect results for tables without primary key
 

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  1. POLINQ to Entities returning incorrect results for tables without primary key
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    <p>I have found that LINQ to Entities needs a primary key on the table in order to return correct results. Without it, I get the expected number of rows but including duplicates (and accordingly, missed rows). This problem is described <a href="https://stackoverflow.com/a/6082816/629287"><strong>here</strong></a> and <a href="https://stackoverflow.com/questions/9415799/linq-to-sql-query-has-wrong-values-in-results"><strong>here</strong></a>, and I consider it to be a bug.</p> <p>In one of my tables, each row is unique but I cannot create a compound key across all fields because nullable columns cannot be used in primary keys (again, I consider this a SQL Server limitation).</p> <p>So... how can I get correct results when selecting from this table using LINQ to Entities? I believe the "key" may be to create an "Entity Key" across all columns in the Visual Studio model designer but I'm not sure how to do this. Setting Entity Key = true on nullable columns throws an exception.</p> <p>At one stage I gave up and added an identity int column with auto-increment enabled and used that as PK, which solved the issue, but I had to throw this out because of the volume of data being deleted/inserted all the time (it's not possible to simply reset the auto-increment counter on a schedule because not all of the rows are deleted, causing clashes).</p> <p>My last resort will be to add a bigint identity column as PK, get rid of the auto-increment seed value resetter and hope it lasts "long enough" for the life of the application, but I'm not comfortable with this. (Edit: OK... it will last long enough. My main concern is performance)</p>
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    1. PTQuestion
    1. USCommunity
    1. USChris
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    1. PL
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      1. LTLinked
    2. PL
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      1. LTLinked
    1. This table or related slice is empty.
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    1. COEvery serious table ***ought to have a primary key*** ....
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      1. POLINQ to Entities returning incorrect results for tables without primary key
      1. USmarc_s
    2. COA `bigint` identifier, if you are inserting 10,000 rows per second, should last you about 29 million years. Is that long enough?
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      1. POLINQ to Entities returning incorrect results for tables without primary key
      1. USTim Rogers
    3. COI can only feel pity for a programmer living in the year 29,002,013 that needs to rebuild the PK on a 29 million year old database.
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      1. POLINQ to Entities returning incorrect results for tables without primary key
      1. USFlater
 

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