After a table in a data module source is updated, you can add or remove individual
columns in the data module without updating the whole table.
This functionality can be used for the following scenarios:
- A source column was deleted from a data module table, the data module was modified and saved,
and the modeler wants to re-add the deleted column to the data module.
- A new column was added to an existing table in a database, and the modeler wants to use this
column in the data module.
- A column was removed or renamed in a database, and the modeler must update the data module to
avoid validation errors.
About this task
For data modules that are based on data servers, use the Reload metadata
function to reload the latest schema metadata from the database. For more information, see Reloading the schema metadata.
Procedure
-
Open the data module that you want to update.
- Click the Source view icon to open the Sources panel, and expand
the source tree.
- If the source is a database server schema, from the schema context menu , click Reload metadata.
Tip: You don't need to perform this step if the database server schema was already
reloaded in the
Data server connections administration user interface after a
database change that needs to be reflected in
Cognos®
Analytics. For more information,
see Loading metadata.
The tables and columns are reloaded based on the latest state of the data server.
- In the Sources panel toolbar, click the Source tree
settings icon , and select the Show unused items check box.
- The columns (and their tables) that are not in the data module are highlighted in the
Sources panel.
- If the source contains renamed columns, or columns were removed from the source, validation
error icons appear next to the affected columns in the Data module
panel.
- In the Sources panel, identify the column that you need to add to
the data module, and drag the column to the related table in the Data module
panel. Expand the table if you want to drop the column into a specific place in the table.
You can drag multiple columns from the same table at once.
- If the data module contains validation errors, the columns in the module might be missing
or renamed in the source. Use the following steps to resolve the errors:
- Drag the renamed columns to the Data module
panel.
- Remove the columns that no longer exist in the source from the data
module.
- Validate the data module.
Potential validation errors might be related to the broken references in expressions, such as
filters or calculations, that might still refer to the removed columns. Using information in the
error messages, manually update these expressions.
- Save the data module.