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PODon't know how to generate the query I need using Entity Framework 4
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  1. PODon't know how to generate the query I need using Entity Framework 4
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    copied!<p>I've got an Entity Framework 4 model. There's 2 tables in that model, Subscribers and Versions:</p> <pre><code>CREATE TABLE tracking."Subscribers" ( "SubscriberId" UUID NOT NULL, "RemoteAddress" VARCHAR(80) NOT NULL, "Priority" INTEGER NOT NULL DEFAULT 100, "DataTypeId" INTEGER NOT NULL REFERENCES tracking."DataTypes" ( "DataTypeId" ), "Condition" VARCHAR(8000), "Version" BIGINT NOT NULL DEFAULT 0, "LastConnected" TIMESTAMPTZ NOT NULL, CONSTRAINT "Subscribers_pkey" PRIMARY KEY ("SubscriberId", "DataTypeId") ); CREATE TABLE tracking."Versions" ( "ObjectId" UUID NOT NULL, "Source" UUID NULL, "From" BIGINT NOT NULL, "To" BIGINT NULL, "DataTypeId" INTEGER NOT NULL REFERENCES tracking."DataTypes" ( "DataTypeId" ), CONSTRAINT "Versions_pkey" PRIMARY KEY ("ObjectId", "DataTypeId") ); </code></pre> <p>Yes, there is a third table, DataTypes, but it's a lookup table &amp; isn't important.</p> <p>Also, you need to know that the values stored in the From &amp; To columns in the Versions table represent version numbers. If the To column is not null, it means that the particular item represented by ObjectId has been deleted from the database.</p> <p>In my C# code, I need to build a query. There is a Dictionary which contains one entry for each combination of data type ID &amp; version number. I need to build a series of tests spearated by ORs, not ANDs.</p> <p>Normally, to build the condition as a string for use in a DbCommand, I'd use code like this:</p> <pre><code>bool isFirst = true; string query = "..."; foreach ( KeyValuePair&lt;int, long&gt; version in versionsLastSent ) { if ( ! isFirst ) { query += " OR "; } query += "...."; isFirst = false; } </code></pre> <p>However, I don't know how to get that OR into the query using entity framework. I know that my query will be a generic IQueryable object and that I add conditions to it using</p> <pre><code>query = query.Where( a =&gt; ... ); </code></pre> <p>But these are normally separated by ANDs. I need ORs.</p> <p>How do I do this?</p> <p>Tony</p> <p>Edit:</p> <p>I forgot to mention that the query needs to look like this when done:</p> <p>SELECT * FROM Versions JOIN Subscribers . . . WHERE &lt;Some Condition&gt; AND ( VersionCondition1 OR VersionCondition2 OR . . . )</p>
 

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