You can use the SCHEMA-CHANGE attribute during an ABL session to perform a growing range of schema maintenance while the database is running.

The SCHEMA-CHANGE attribute relaxes the requirement for exclusive access to a database in order to make the following schema changes online:

  • Add new sequences.
  • Add new tables, as well as any associated fields, indexes, and database triggers (which must be added within the same transaction).
  • Add new fields to an existing table.
    Note: When an add field operation is performed online, the connected clients can access (perform read/write operation on) the newly created field without disconnecting or refreshing their schema cache. For this to happen, during an online field creation, a DB notification is sent to all other connected clients, so that, they can refresh their schema cache at the end of their active transactions.
  • Add new inactive indexes to an existing table.

The attribute must be set to "NEW OBJECTS" to activate this feature.

Notes