Sequences and Identity Columns

  • Sequences are supported on source and target tables for unidirectional, bidirectional, and multi- directional implementations.

  • Identity columns created using the GENERATED BY DEFAULT AS IDENTITY clause are supported on source and target tables, for unidirectional, bidirectional, and multi- directional implementations.

  • Identity columns created using the GENERATED ALWAYS AS IDENTITY clause are not supported in target database tables and the Identity property should be removed from target tables or changed to GENERATED BY DEFAULT AS IDENTITY.

  • For bidirectional and multi-directional implementations, define the Identity columns and sequences with an INCREMENT BY value equal to the number of servers in the configuration, with a different MINVALUE for each one.

    For example, MINVALUE /INCREMENT BY values for a bidirectional, two-database configuration would be as follows:

    Database1, set the MINVALUE at 1 with an INCREMENT BY of 2.

    Database2, set the MINVALUE at 2 with an INCREMENT BY of 2.

    For example, MINVALUE /INCREMENT BY values for a multi-directional, three-database configuration would be as follows:

    Database1, set the MINVALUE at 1 with an INCREMENT BY of 3.

    Database2, set the MINVALUE at 2 with an INCREMENT BY of 3.

    Database3, set the MINVALUE at 3 with an INCREMENT BY of 3.