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POWhy does EF 5.0 not support this EF 4.x LINQ syntax when compiling to sql?
 

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  1. POWhy does EF 5.0 not support this EF 4.x LINQ syntax when compiling to sql?
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    <p>I have some code that was recently upgraded from EF 4.2 to EF 5.0 (actually EF 4.4 since I am running on .Net 4.0). I have discovered that I had to change the syntax of my query, and I'm curious as to why. Let me start off with the problem.</p> <p>I have an EventLog table that is populated by the client periodically. For each event log an entry is created in a Report table. This is the query that is run periodically to discover any event logs that do not have an entry in the Report table yet. The query I used in EF 4.2 was:</p> <pre><code>from el in _repository.EventLogs where !_repository.Reports.Any(p =&gt; p.EventLogID == el.EventlogID) </code></pre> <p>Since upgrading to EF 5.0 I get the following error at runtime:</p> <blockquote> <p>System.NotSupportedException: Unable to create a constant value of type 'Namespace.Report'. Only primitive types or enumeration types are supported in this context.</p> </blockquote> <p>I discovered that rewriting it with the join syntax fixed the issue. The following works in EF 5.0 and is roughly the equivalent:</p> <pre><code>from eventLog in _repository.EventLogs join report in _repository.Reports on eventLog.EventlogID equals report.EventLogID into alreadyReported where !alreadyReported.Any() </code></pre> <p>Some people may have mixed opinions about the mixed syntax/style of the first query, but I'm really more interested in the why of this. It seems odd that the EF 4.2 compiler could generate the SQL for the original query but that the EF 5.0 refuses. Is this a setting I am missing or just a tightening of constraints between the two? Why is this happening?</p>
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    1. USAndrew Dunaway
    1. USAndrew Dunaway
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      1. POWhy does EF 5.0 not support this EF 4.x LINQ syntax when compiling to sql?
      1. USPhil Figgins
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      1. POWhy does EF 5.0 not support this EF 4.x LINQ syntax when compiling to sql?
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      1. VTUpMod
    1. COPersonally I think it's much more readable as a query with the join..
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      1. POWhy does EF 5.0 not support this EF 4.x LINQ syntax when compiling to sql?
      1. USSimon Whitehead
    2. COCould you test this instead `from el in _repository.EventLogs where _repository.Reports.All(p => p.EventLogID != el.EventlogID)` ?
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      1. POWhy does EF 5.0 not support this EF 4.x LINQ syntax when compiling to sql?
      1. USKing King
    3. COHey King, I tried that and got the same thing. I even tried: !_repository.OntarioReports.Any(p => 5 == 5). It seems to be the mixed syntax from what I can tell.
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      1. USAndrew Dunaway
 

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