Dynamic mapping tasks automatically use dynamic schema change handling. This means that Data Integration refreshes the schema of applicable source, target, and lookup objects every time you run the task.
A schema change includes one or more of the following changes:
•Fields are added.
•Fields are deleted.
•Fields are renamed.
•Field data type, precision, or scale is updated.
Data Integration updates the schema for data objects with connectors which support dynamic schema handling. A connector that supports dynamic schema handling in mapping tasks supports this functionality in dynamic mapping tasks. You can configure the applicable dynamic schema handling options similar to in a mapping task. To see if a connector supports dynamic schema change handling, see the help for the appropriate connector. Data Integration does not update the schema for hierarchical data objects.
If you update fields in the source object, be sure to update the Target transformation field mapping. Data Integration writes Null to the target fields that were previously mapped to the renamed or deleted source fields.
Schema change handling options
You can choose how Data Integration applies dynamic schema changes from upstream transformations to the target. If the mapping contains more than one target, select the schema change handling for each target.
Configure schema change handling options in the target object settings. Schema change handling options configured within a job override default schema options.
To select schema options, the target field mapping in the referenced mapping must be automatic.
The schema change handling options available are based on the target type. The following table describes the options that you can select for each target type:
Schema handling option
Target type
Description
Keep Existing File Format
File
Data Integration fetches the most recent target schema at runtime and does not apply upstream schema changes to the target file.
Drop Current and Recreate
Database and file
For database targets, Data Integration drops the existing target table and creates a new target table with the schema from the upstream transformations on every run.
For file targets, Data Integration updates the target schema to match the incoming schema on every task run.
Alter and Apply Changes
Database
Data Integration updates the target schema with additive changes to match the schema from the upstream transformations. It does not delete columns from the target.
Don't Apply DDL Changes
Database
Data Integration fetches the target schema at runtime and does not apply upstream schema changes to the target table.
Data Integration does not pass field constraints to the target. For example, the source contains fields S1 and S2 configured with the NOT NULL constraint. The target contains fields T1 and T2 also configured with the NOT NULL constraint. You select the Alter and Apply Changes schema handling option. When you run the task, fields S1 and S2 are written to the target with no constraints.