Defining variables in SQL statements

Elements of SQL statements can be executed as map sources that are determined at runtime. Use the Database Interface Designer to define a statement variable with a pseudo value in an SQL statement and then pass the actual value on the command line at runtime. This technique is beneficial when using the RUN function because it allows one map to modify the SQL statement of another map or to build, potentially, an entire SQL statement.

When you generate type trees using the Database Interface Designer, a substitution value must be entered for each variable to ensure that the syntax of the SQL statement is valid. The Database Interface Designer provides a facility for specifying a value for these variables; however, the value you enter for a variable in the Database Interface Designer does not have to be the same value passed at runtime. (Any value can be passed.)