This topic describes incompatibilities between MySQL databases and MySQL tenants of OceanBase Database when you change the length of an unconstrained column.
The following table describes the operations that you can perform to change the length of a column by executing the ALTER TABLE table_name MODIFY/CHANGE COLUMN DDL statement in a MySQL database and a MySQL tenant of OceanBase Database.
In the table, a hyphen (-) means N/A.
Column type in a MySQL database | Allowed operation | Column type in a MySQL tenant of OceanBase Database | Allowed operation |
INT | Increase and decrease the length | INTEGER | Increase and decrease the length |
TINYINT | Increase and decrease the length | TINYINT | Increase and decrease the length |
SMALLINT | Increase and decrease the length | SMALLINT | Increase and decrease the length |
MEDIUMINT | Increase and decrease the length | MEDIUMINT | Increase and decrease the length |
BIGINT | Increase and decrease the length | BIGINT | Increase and decrease the length |
BOOL | - | BOOLEAN | - |
DECIMAL | Increase and decrease the length | DECIMAL | Increase the length |
NUMERIC | Increase and decrease the length | NUMERIC | Increase the length |
REAL | Increase and decrease the length | FLOAT | Increase and decrease the length |
DOUBLE | Increase and decrease the length | DOUBLE | Increase and decrease the length |
FLOAT | Increase and decrease the length | FLOAT | Increase and decrease the length |
BIT | Increase and decrease the length | BIT | Increase and decrease the length |
CHAR | Increase and decrease the length | CHAR | Increase the length |
NCHAR | Increase and decrease the length | CHAR | Increase the length |
VARCHAR | Increase and decrease the length | VARCHAR | Increase the length |
BINARY | Increase and decrease the length | BINARY | - |
VARBINARY | Increase and decrease the length | VARBINARY | Increase the length |
LONG_VARBINARY | - | BLOB | - |
YEAR | Increase and decrease the length | YEAR | Increase the length (However, the length is actually fixed at 4 bytes.) |
DATE | - | DATE | - |
TIME | Increase and decrease the length | TIME | Increase the length |
TIMESTAMP | Increase and decrease the length | TIMESTAMP | Increase the length |
DATETIME | Increase and decrease the length | DATETIME | Increase the length |
TINYBLOB | - | TINYBLOB | - |
MEDIUMBLOB | - | MEDIUMBLOB | - |
BLOB | - | BLOB | - |
LONGBLOB | - | LONGBLOB | - |
TINYTEXT | - | TINYTEXT | - |
MEDIUMTEXT | - | MEDIUMTEXT | - |
TEXT | - | TEXT | - |
LONGTEXT | - | LONGTEXT | - |
ENUM | Increase and decrease the length | ENUM | Increase the length |
SET | Increase and decrease the length | SET | Increase the length |
JSON | - | JSON | - |