Schemas Defined in a Transformation¶
Schemas used in a transformation either are inherited from connector activities that are initially adjacent to a transformation or are defined in a transformation, as described in this section. A schema defined in an adjacent activity (or an initially adjacent activity that has since been removed) takes precedence over a schema defined in a transformation (see How Schemas Are Defined in Schema Usage).
These are the various ways to create a schema directly in a transformation:
- Custom Flat Schema
A flat schema is a simple, one-level field structure that has the same data row type throughout the text document. Custom flat schemas are created in CSV format. Once created, they can be edited at any time.
- Custom Hierarchical Schema
A hierarchical schema is a complex file structure that contains multiple file row types such as header or summary rows. Custom hierarchical schemas can be created in XML or CSV format. Once created, they can be edited at any time.
- Sample File Schema
If you already have a file available that contains the structure of data you want to use, you can use a sample file within a transformation. Once a sample file is uploaded, it becomes a custom schema that you can edit in the schema editor for a custom flat schema or custom hierarchical schema.
- Mirrored Schemas
If you are using a schema on the source or target side of a transformation and want to copy its structure to use on the other side of the transformation, you can mirror the schema within the transformation. Once a schema is mirrored, it becomes a custom schema that you can edit in the schema editor for a custom flat schema or custom hierarchical schema.
- Schema Previously Provided by an Inherited Activity
The ownership of a schema that was originally defined in an activity and is being inherited by a transformation is transferred to the transformation when the activity providing the schema is deleted.