You can use PDM variables and macros to write SQL statements.
In the following example, a trigger written using the PDM variables and macros is attached to the Example table, and writes the contents of any insertion to HistoryTable.
The actual trigger code can be viewed on the Preview tab:
For lists of the available variables and macros, see Customizing and Extending PowerDesigner > DBMS Definition Files > PDM Variables and Macros.
See Writing SQL using GTL for an example of the same trigger written using the PowerDesigner GTL.