title: Prefixing table names causes discriminator column to be removed
body: <p>I have a lookup table that is fairly simple</p>
  
  <pre><code>public class LookupType : Entity
  {
      public LookupType()
      {
      }
  
      public LookupType(string value)
      {
          Value = value;
      }
  
      public string Value { get; set; }
  
      // A few other properties
  }
  </code></pre>
  
  <p>And a few classes that inherit from it</p>
  
  <pre><code>public class SomeType : LookupType
  {
      public SomeType() 
      {
      }
  
      public SomeType(string value) 
          : base(value)
      {
      }
  }
  </code></pre>
  
  <p>I also have the following mapping for the LookupTypes in the <code>OnModelCreating</code> method.</p>
  
  <pre><code>// Lookup Types
  modelBuilder.Entity&lt;LookupType&gt;()
              .Map&lt;SomeType&gt;(m =&gt; m.Requires("LookupType").HasValue("Some Type"));
  </code></pre>
  
  <p>Now this works fine for what I need it to do. The migration will create the table along with the column <code>LookupType</code> as the discriminator. </p>
  
  <pre><code>CreateTable(
              "dbo.LookupTypes",
              c =&gt; new
                  {
                      Id = c.Int(nullable: false, identity: true),
                      DisplayOrder = c.Int(nullable: false),
                      Value = c.String(),
                      TimeStamp = c.Binary(nullable: false, fixedLength: true, timestamp: true, storeType: "rowversion"),
                      LookupType = c.String(maxLength: 128),
                  })
              .PrimaryKey(t =&gt; t.Id);
  </code></pre>
  
  <p>However I need to prefix my table names. So in the <code>OnModelCreating</code> method of my context I add the following line</p>
  
  <pre><code>modelBuilder.Types().Configure(entity =&gt; entity.ToTable("abc_" + entity.ClrType.Name));
  </code></pre>
  
  <p>The <code>LookupType</code> column is now gone when creating the migrations.</p>
  
  <pre><code>CreateTable(
              "dbo.abc_LookupType",
              c =&gt; new
                  {
                      Id = c.Int(nullable: false, identity: true),
                      DisplayOrder = c.Int(nullable: false),
                      Value = c.String(),
                      TimeStamp = c.Binary(nullable: false, fixedLength: true, timestamp: true, storeType: "rowversion"),
                  })
              .PrimaryKey(t =&gt; t.Id);
  </code></pre>
  
  <p>I know the prefix configuration is the line that's causing issues because commenting it out and regenerating the migrations will bring the LookupType column back.</p>
  
  <p>The column definitions shouldn't be changing, so why is the discriminator column being removed? Is there any way around this so I can keep the discriminator column and prefix the tables?</p>