SQLite Error: Cannot delete WhereListIterator`1: it has no PK <p>I'm trying to delete records from a database using SQLite/C# in Visual Studio 2012. Whenever I attempt to delete a record I get the following error:</p> <pre><code>SQLite Error: Cannot delete WhereListIterator`1: it has no PK </code></pre> <p>I am wanting to delete records using two different methods. Either delete using only the EID, which is the primary key, or delete records where the user provides everything but the EID.</p> <pre><code> if (EID_TextBox.Text != String.Empty) { if (Roster_Enrollment.Any(x =&gt; x.EID.Equals(Int32.Parse(EID_TextBox.Text)))) { App.DBConnection.Delete(Roster_Enrollment.Where(x =&gt; x.EID.Equals(Int32.Parse(EID_TextBox.Text)))); Message_TextBlock.Text = "Enrollment deleted."; } else { Message_TextBlock.Text = "Enrollment not found."; } } else if (Roster_Enrollment.Any(x =&gt; x.CourseNo.Equals(CourseNo_TextBox.Text) &amp;&amp; x.SectionNo.Equals(SectionNo_TextBox.Text) &amp;&amp; x.Tno.Equals(Tno_TextBox.Text))) { App.DBConnection.Delete(Roster_Enrollment.Where(x =&gt; x.CourseNo.Equals(CourseNo_TextBox.Text) &amp;&amp; x.SectionNo.Equals(SectionNo_TextBox.Text) &amp;&amp; x.Tno.Equals(Tno_TextBox.Text))); } else { Message_TextBlock.Text = "Enrollment not found."; } </code></pre>