External Table Option

If the data is to be joined with other tables or requires complex transformations, then use the External Table option. An external table can be used as a source and enables data from the associated flat file to be viewed from SQL as a table. When you use an external table in a mapping, its column properties are based on the SQL properties that you defined when importing the flat file. OWB generates SQL code to select rows from the external table. You can also get parallel access to the file through the table. You can either import an existing external table from another database or define a new external table.

You can also use an external table to combine the loading and transformation within a single set-based SQL DML statement. You do not have to stage the data before inserting it into the target table.