You can clear a target table in the following ways:

The first two tokens in the SQL can be either TRUNCATE TABLE or DELETE FROM. The final tokens in the SQL define the fully qualified table from which the data map can be determined. For example, you could use one of the following statements:

If you select the

Truncate target option

session property or the

Truncate Target Table

ODBC property, PowerExchange generates a statement, which you cannot modify, in one of these forms.

The system loads the data map for the table and determines the underlying map type.

For map types of ESDS, KSDS, RRDS, SEQ, or TAPE, the file defined in the data map (or overridden at run time) is opened in write mode and closed so that existing contents of the file are cleared. This method of clearing files is useful because otherwise, if no data is processed in a workflow, the output file might contain records from an earlier run that are retained. PowerExchange defers opening of output files until actual data is being written.

The entire file is always cleared. In the case of multiple-record files, any of the table names can be chosen and data for all tables is cleared. Although it is physically possible for an individual table to be cleared from KSDS and RRDS files, you cannot achieve this result by defining TRUNCATE TABLE or DELETE FROM in the

Pre SQL

session property. It might be possible to clear part of a KSDS file using DELETE SQL with a WHERE clause that is run as part of a workflow, but not by defining the statement in the

Pre SQL

session property.

Clearing a target table by using one of these methods is not supported for other data map types.