Modifying Schema Entities › Set Modifications › Adding and Dropping Set Pointers

Adding and Dropping Set Pointers

Types of changes

You can make the following changes to set pointers:

• Add or remove prior or owner pointers from a chain set
• Add or remove owner pointers from an indexed set

What components are affected

When you change the prior or owner pointers defined to a set, the schema set definition and data are affected. Subschemas and access modules that reference either the owner or member records are also affected.

Steps to add or drop set pointers

To add or drop set pointers when data has been loaded:

1. Create a new schema based on the original schema but containing the modified set pointers
2. Validate the schema
3. Create a global subschema
4. Use the schema compare utility (IDMSRSTC) to generate the IDMSRSTT macro statements
5. Restructure the database using RESTRUCTURE
6. If you add a prior or owner pointer to an existing set, fill in the pointer values using RESTRUCTURE CONNECT
7. Complete the process by modifying the original schema, regenerating affected subschemas, and altering affected access modules.

Considerations

• When adding or deleting pointers, do not use the AUTO parameter; specify the actual pointer positions. This eliminates the possibility the schema compiler will identify different pointer positions than exist in the loaded database.
• When deleting a pointer from a set in a schema and a participating record contains pointer positions beyond the deleted pointer, you must renumber the remaining positions. You cannot leave unused pointer positions.