Modifying Schema Entities › Index Modifications › Adding or Deleting System-Owned Indexes

Adding or Deleting System-Owned Indexes

What components are affected

When you add or remove a system-owned index, the schema set definition and the data are affected. All subschemas and access modules that reference the member record are also affected.

Steps to add an index

To add an index when data has been loaded:

1. Add a new schema based on the original schema adding the new index
2. Validate the schema
3. Create a global subschema for the new schema
4. If the index is linked, add the index pointer position to the member record using the schema compare utility (IDMSRSTC) and RESTRUCTURE
5. Build the index structure using the new subschema using the MAINTAIN INDEX utility statement
6. Complete the process by updating the original schema, regenerating affected subschemas, and altering affected access modules

Steps to remove an index

To remove an index when data has been loaded:

1. Add a new schema based on the original schema removing the index
2. Validate the schema
3. Create a global subschema for the new schema
4. Delete the index structure using an old subschema and the MAINTAIN INDEX utility statement
5. If the index is linked, remove the index pointed from the member record using the schema compare utility (IDMSRSTC) and the RESTRUCTURE utility statement
6. Complete the process by updating the original schema, regenerating affected subschemas, and altering affected access modules

Considerations

• The index you delete from the schema will automatically be deleted from any affected subschemas when you request that affected subschemas be regenerated.
• If an index is added or removed, it may change the control length of the record. If it does and the record is compressed or variable in length, you must change the control length of existing data using RESTRUCTURE.