Use pre-SQL with the RETAIN strategy in a mapping to retain the existing Delta Lake target table, including its data, and add columns to it.
Create a passthrough mapping with ports dynamically linked from the Read transformation to the Write transformation.
Select the Write transformation and the Advanced property sheet. For Target Schema Strategy, select
Open the Advanced property sheet. Use an ALTER TABLE Pre-SQL statement to specify the columns from the source schema to add to the target table schema.
You can choose to put the Pre-SQL query itself into the PreSQL property, or use a parameter or parameter set that contains the query. For more information about using parameterization in mappings, see the
Informatica Developer Tool Guide
Informatica Developer Mapping Guide
The following image shows the PreSQL property location in the Advanced properties:
The following image shows the PreSQL property with a parameter as a value: