Supported DDL operations in incremental migration from an Oracle database to an Oracle tenant of OceanBase Database

Supported DDL operations in incremental migration

• CREATE TABLE

  You can create partitioned tables but cannot use CREATE TABLE AS SELECT to create tables.

• DROP TABLE

• TRUNCATE TABLE

• ADD PARTITION

  You can add partitions and subpartitions by using RANGE or LIST partitioning. HASH partitioning is not supported.

• DROP PARTITION

  You can drop one or more partitions and subpartitions.

• TRUNCATE PARTITION

  You can truncate one or more partitions and subpartitions.

• RENAME TABLE and ALTER TABLE RENAME

• ALTER TABLE ADD COLUMN

• ALTER TABLE MODIFY COLUMN

  Notice

  You can only extend the column length. You cannot modify the column type.

• ALTER TABLE DROP COLUMN

• CREATE INDEX

• DROP INDEX

• Adding comments to tables or columns

Limits of DDL operations in incremental migration

• If a table to be synchronized involves DDL operations that are not supported, the migration link may be interrupted and unrecoverable data exceptions may be caused.

• Frequent DDL operations on a table are not supported. After the store finishes a DDL operation, which can be determined based on the timestamp, it proceeds to the next DDL operation. Otherwise, the store may exit unexpectedly or cause unrecoverable data exceptions.

• Make sure that no DDL operations are performed before you create a store and when a store is being started. If log pulling is involved, make sure that no DDL operations are performed during the period from the start time when logs are pulled to the current time. Otherwise, the store may exit unexpectedly or cause unrecoverable data exceptions.

• The table names before and after the RENAME TABLE statement must be both included or both not included in the list of tables to be synchronized.

• If you delete an unnamed primary key, the corresponding constraint whose name starts with SYS_C in the Oracle database is deleted. If you perform inter-database data migration or synchronization, for example, from an Oracle database to an OceanBase database, the primary keys in the OceanBase database cannot be deleted because they are different from those in the Oracle database.

• A table creation DDL operation that involves the CASE WHEN INDEX clause cannot be synchronized.

• If you enable DDL operations in incremental migration, the DROP INDEX statement is executed on all indexes, which may cause index loss in the destination database.