This topic describes CREATE TABLE DDL operations that are executed in a MySQL database and can be converted by the DDL synchronization component of OceanBase Migration Service (OMS), but they cannot be executed in the MySQL-compatible tenant of OceanBase Database when you migrate data from the MySQL database to the MySQL-compatible tenant of OceanBase Database.
Define a generated column based on other generated columns
Use other generated columns in the CREATE TABLE DDL statement to define a newly generated column.
MySQL databases: supported.
MySQL-compatible tenants of OceanBase Database: not supported.
Example:
CREATE TABLE group_by_t1
(a INT GENERATED ALWAYS AS (1) VIRTUAL,
b INT GENERATED ALWAYS AS (a) VIRTUAL,
c INT GENERATED ALWAYS AS (1) VIRTUAL);
Create an index or a constraint
When you create a constraint, the column types supported in a MySQL database are different from those supported in a MySQL-compatible tenant of OceanBase Database. For more information, see Column types that are supported to create indexes or constraints.
Limitations on creating a FOREIGN KEY constraint:
MySQL-compatible tenants of OceanBase Database: The referenced column in the parent table must have the UNIQUE KEY or PRIMARY KEY constraint when you create a foreign key.
MySQL databases: The referenced column in the parent table must have the UNIQUE KEY, PRIMARY KEY, or KEY constraint when you create a foreign key.
