The following is copied from the docs:
DQE Compatibility mode(SqlServer only)
With the arrival of SqlServer 2005 and its new features, it was required to make the SqlServer DQE be configurable so it could generate SQL which was optimal for the database type used. To set the compatibility mode of the SqlServer DQE in code, you can use the DataAccessAdapter method SetSqlServerCompatibilityLevel, as shown in the following example which sets the compatibility mode to SqlServer 2005:
// C#
DataAccessAdapter.SetSqlServerCompatibilityLevel( SqlServerCompatibilityLevel.SqlServer2005 );
The different compatibility modes are:
SqlServerCompatibilityLevel.SqlServer7 (or the value 0)
SqlServerCompatibilityLevel.SqlServer2000 (or the value 1)
SqlServerCompatibilityLevel.SqlServer2005 (or the value 2)