Columns Tab

This displays the column meta data for the selected input link in a grid.

There are various ways of populating the grid:

• If the other end of the link has meta data specified for it, this will be displayed in the Columns tab (meta data is associated with, and travels with, a link).
• You can type the required meta data into the grid. When you have done this, you can click the Save... button to save the meta data as a table definition in the Repository for subsequent reuse.
• You can load an existing table definition from the Repository. Click the Load... button to be offered a choice of table definitions to load. Note that when you load in this way you bring in the columns definitions, not any formatting information associated with them (to load that, go to the Format tab).
• You can drag a table definition from the Repository Window on the Designer onto a link on the canvas. This transfers both the column definitions and the associated format information.

If you select the options in the Grid Properties dialog box (see Grid properties for more information), the Columns tab will also display two extra fields: Table Definition Reference and Column Definition Reference. These show the table definition and individual columns that the columns on the tab were derived from.

If you click in a row and select Edit Row... from the shortcut menu, the Edit Column Meta Data dialog box appears, which allows you edit the row details in a dialog box format. It also has a Parallel tab which allows you to specify properties that are peculiar to parallel job column definitions. The dialog box only shows those properties that are relevant for the current link.

The Parallel tab enables you to specify properties that give more detail about each column, and properties that are specific to the data type. Where you are specifying complex data types, you can specify a level number, which causes the Level Number field to appear in the grid on the Columns page.

If you have NLS enabled, and the column has an underlying string type, you can specify that the column contains Unicode data by selecting the Extended (Unicode) check box. Where you can enter a character for any property, this can usually be an ASCII character or a multi-byte Unicode character (if you have NLS enabled).

Some table definitions need format information. This occurs where data is being written to a file where InfoSphere® DataStage® needs additional information in order to be able to locate columns and rows. Properties for the table definition at row level are set on the Format tab of the relevant stage editor, but you can override the settings for individual columns using the Parallel tab. The settings are made in a properties tree under the following categories: