Utility Statements › REORG › Usage › Implementing Changes Through REORG

Implementing Changes Through REORG

Changing an SQL-defined database

You use REORG on an SQL-defined database to modify the database based on changes made to its segment definition. These changes must be reflected in the target DMCL. The modified DMCL must be available during the entire REORG operation, including the setup and unload phases.

You can make the following changes using REORG:

• Change area page ranges
• Change page size

  See EXPAND PAGE for an alternative means of changing a page size.

• Change the maximum number of records per page

  See CONVERT PAGE for an alternative means of changing the maximum number of records per page.

The names of the source and target segments for a REORG operation on an SQL-defined database must be the same. Consequently, if you are making any of the previous changes, you must specify a target DMCL whose name differs from that of the source DMCL. For more information about the DMCLs used by the REORG utility, see the source/target DMCLs in Initiating a REORG Operation.

You cannot make changes to table definitions in an SQL-defined database between the setup and reload phases of a REORG operation.

Changing a non-SQL-defined database

You use REORG on a non-SQL-defined database to modify the database based on changes made to its schema or segment definitions. These changes must be reflected in the target subschema and DMCL. The modified DMCL and subschema must be available during the entire REORG operation, including the setup and unload phases.

You can make the following changes using REORG:

• Change area page ranges
• Change page size

  See EXPAND PAGE for an alternative means of changing a page size.

• Reassign records to different areas or page ranges

  Note: The record names must match in the source and target subschemas.

• Change record placements within an area
• Change record location modes
• Store VIA records by means of a different set (as long as they already participate in the set)
• Change compression and INDEX BLOCK CONTAINS options for indexes
• Change area and page-range assignments for system-owned indexes
• Change the maximum number of records per page

  See CONVERT PAGE for an alternative means of changing the maximum number of records per page.

• Add fields to an existing index key provided the fields already exist
• Remove fields from an index
• Change an index from unsorted to sorted provided the key fields already exist

  Note: Duplicate key order is random.

• Change an index from sorted to unsorted

Changes that cannot be implemented using REORG

The REORG utility cannot be used against native VSAM files.

During REORG processing, record formats and set relationships are preserved. This limits the modifications that you can make during a REORG operation. For example, you cannot use a REORG operation to:

• Remove a set
• Remove a record type
• Insert new data fields into a record
• Remove fields from a record
• Change the order of a sorted chained set
• Connect records to new chained or user-owned index sets
• Change the size, location, or data type of sort or index keys
• Change a chained set from unordered to ordered

These types of changes require other utilities, such as RESTRUCTURE, and possibly user-written programs.