Create a field expression to change the value, datatype, scale, or precision of a field. For example, you create a case-sensitive join condition between two columns that have the same values. However, the values have different cases. To match the values, you can include a field expression for each column in the join condition to convert all values to uppercase letters.

Create different types of filter expressions to increase test performance. A filter reduces the number of records that are processed in single-table or table-pair tests. For example, you can create a WHERE clause expression in a single table definition to process a subset of the records in a relational table.

You create expressions in the Expression Editor. You can manually enter an expression. Or, you can select fields, PowerCenter functions, and Data Validation Option parameters from the Expression Editor. If you create an expression for a test condition, you can also select an operator to compare two values.

When you create an expression, you must use the proper syntax based on the component that processes the expression. By default, PowerCenter processes expressions. However, you can configure the data source to process some expressions.

You must also enter a valid expression. You can validate PowerCenter expressions in the Expression Editor.

You can use one or more parameters in the WHERE clauses of table pairs and single tables. Use parameters in the WHERE clause to dynamically change the WHERE clause after each test run.