WHERE Clause Driving Table

The WHERE Clause Driving Table setting tells the Analytical Engine the type of column that is preferred in the qualification of a WHERE clause. One SQL pass usually joins fact tables and lookup tables on certain ID columns. When a qualification is defined on such a column, the Analytical Engine can use the column in either the fact table or the lookup table. In certain databases like Teradata and RedBrick, a qualification on the lookup table can achieve better performance. The Analytical Engine tries to pick the column from the lookup table when the WHERE Clause Driving Table property is set to use the lookup table.

If this property is set to lookup table, but no lookup table exists in the FROM clause for the column being qualified on, the Analytical Engine does not add the lookup table to the FROM clause. To ensure that the qualification uses a lookup table column, set the DSS Star Join setting to use a partial star join.

For more information on the DSS Star Join setting, see the System Administration Guide.

The options for this property are

• Use lookup table
• Use fact table
• Use default inherited value