External Source stage
The External Source stage is a file stage that allows you to read data that is output from one or more source programs.
The External Source stage is a file stage. It allows you to read data that is output from one or more source programs. The stage calls the program and passes appropriate arguments. The stage can have a single output link, and a single rejects link. It can be configured to execute in parallel or sequential mode. There is also an External Target stage which allows you to write to an external program (see External Target stage).
When reading output from a program, InfoSphere DataStage needs to know something about its format. The information required is how the data is divided into rows and how rows are divided into columns. You specify this on the Format tab. Settings for individual columns can be overridden on the Columns tab using the Edit Column Metadata dialog box.
When you edit an External Source stage, the External Source stage editor appears. This is based on the generic stage editor described in "Stage Editors."
The stage editor has two pages:
- Stage Page. This is always present and is used to specify general information about the stage.
- Output Page. This is where you specify details about the program or programs whose output data you are reading.
There are one or two special points to note about using runtime column propagation (RCP) with External Source stages. See "Using RCP With External Source Stages" for details.