You can maintain relational target definitions in the following ways:
Reimport the target definition.
Reimport a target definition rather than edit it if the target changes significantly.
Define primary key-foreign key relationships.
Define primary key-foreign key relationships between relational target tables.
Edit the target definition.
Edit a target definition to add comments or key relationships, or update it to reflect a changed target.
After you create a relational target definition, you can edit it using the following target definition tabs:
Edit properties such as constraints for relational targets and flat file properties for flat file targets.
Edit column information such as datatype and precision.
Add index information for relational target definitions.
Metadata Extensions tab.
Extend the metadata stored in the repository by associating information with repository objects, such as target definitions.
When you change a target definition, the Designer propagates the changes to any mapping using that target. Some changes to target definitions can invalidate mappings.
The following table describes how you can impact mappings when you edit target definitions:
Change a column datatype.
Mapping may be invalidated. If the column is connected to an input port that uses a datatype that is incompatible with the new one (for example, Decimal to Date), the mapping is invalid.
Mapping may be invalidated. If you change the column name for a column you just added, the mapping remains valid. If you change the column name for an existing column, the mapping is invalidated.
Mapping may be invalidated if the mapping uses values from the deleted column.
Change the target definition type.
When you add a new column to a target in the Target Designer, all mappings using the target definition remain valid. However, when you add a new column and change some of its properties, the Designer invalidates mappings using the target definition.
You can change the following properties for a newly added target column without invalidating a mapping:
If the changes invalidate the mapping, validate the mapping and any session using the mapping. You can validate objects from the Query Results or View Dependencies window or from the Repository Navigator. You can validate multiple objects from these locations without opening them in the workspace. If you cannot validate the mapping or session from one of these locations, open the object in the workspace and edit it.