Defining and Mapping Table Descriptors

This section contains the following topics.

• About Table Descriptors
  Use Table Descriptors to map executable objects to the tables they read from and write to.
• Creating a Table Descriptor
  There are several ways to create a Table Descriptor.
• Mapping Table Descriptors to Table Instances
  A Program or other executable object instance can read data only when its source Table Descriptors are mapped to the Table instances that contain the source data, and can write data to Table instances only when target Table Descriptors are mapped to the Table instances.
• Mapping Columns
  When you map a Table Descriptor to a Table instance using any method, the system tries to map the Columns at the same time, by name. If the system cannot map the Columns, the mapping status of the Table Descriptor is set to Incomplete.
• Creating and Mapping Table Descriptors and Table Instances at the Same Time
  This section contains information on the following topics.
• Unmapping Table Descriptors
  If a Table Descriptor is mapped to one Table instance and you need to map it to a different Table instance, you must unmap it first.
• Modifying Table Descriptors
  To modify a Table Descriptor, you must also modify its source Table definition. You must check out both the Program, Load Set, Data Mart, or Business Area that contains the Table Descriptor and also check out the source Table definition. You can check out the Table definition from the Table Descriptor.