title: How do ADO.NET DataTable Constraints affect performance?
body: <p>Do constraints on a DataTable (e.g. PrimaryKey &amp; UniqueContraint) make Selects more efficient in the same way that they would in SQL Server? Or is their only purpose to enforce rules on the data?</p>
  
  <pre><code>myDT.Constraints.Add("PK", myDT.Columns["UniqueID"], true); //add a primary key
  myDT.Constrinats.Add(new UniqueConstraint(new DataColumn[] { //add a unique constraint for UserID
      myDT.Columns["UserID"], myDT.Columns["UniqueID"]
  })); 
  </code></pre>
  
  <p>Would these examples potentially have better performance when looking up data in the DataTable by <code>UniqueID</code> or <code>UserID</code>?</p>