CREATE DATABASE-阿里云帮助中心

The CREATE DATABASE statement creates a database. You can specify default properties for the database, such as its character set and collation.

Syntax

create_database_stmt:
    CREATE {DATABASE | SCHEMA} [IF NOT EXISTS] database_name [database_option_list]

database_option_list:
    database_option [database_option ...]

database_option:
    [DEFAULT] {CHARACTER SET | CHARSET} [=] charset_name
  | [DEFAULT] COLLATE [=] collation_name
  |  LOCALITY = locality_option
  | [{PARTITION_MODE|MODE} = partition_mode_option]

locality_option:
    'dn=storage_inst_id_list'

storage_inst_id_list:
    storage_inst_id[,storage_inst_id_list]

partition_mode_option:
     {'auto'|'partitioning'}
    |{'drds'|'sharding'}

Parameters

Parameter	Description
database_name	Specify the name of the database to modify. If this parameter is omitted, the current default database is modified.
CHARSET charset_name	Specify the target character set.
COLLATE collation_name	Specifies the collation.
LOCALITY	Specifies the storage location of the database when it is created. Note After you specify the storage location of a database using the LOCALITY syntax, you cannot change the location.
MODE	Specifies the partitioning mode for the logical database. The following modes are supported: auto/partitioning: AUTO mode If you do not manually specify a partition definition, the database is automatically partitioned by the primary key. You can create tables in the database only using the new CREATE TABLE (AUTO mode) syntax, such as `partition by hash/Range/List`. drds/sharding: DRDS mode. You can create tables in the database only using the CREATE TABLE (DRDS mode) syntax, such as `dbpartition by/tbpartition by`. Important If you do not specify a mode when you create the database, `drds/sharding` is used by default. The partitioning mode of a database cannot be changed after it is specified.

Examples

Create a database named `test` and set its character set to UTF-8.

CREATE DATABASE test default CHARACTER SET=UTF8 mode=auto;
Query OK, 1 row affected (3.36 sec)

Create a database in an instance and store it on the polardbx-storage-0-master node.

CREATE DATABASE db1 LOCALITY='dn=polardbx-storage-0-master';

Note

If you do not specify a storage location when you create a database, the system distributes the database evenly across all storage nodes by default.
The storage location of sharded tables in a database is the same as that of the database. This provides data isolation for the sharded tables.

After the database is created, you can run the following statement to view its storage location information.

SHOW CREATE DATABASE db1;

The following result is returned:

+----------+------------------------------------------------------------------------+
| DATABASE | CREATE DATABASE                                                        |
+----------+------------------------------------------------------------------------+
| db1      | CREATE DATABASE `db1` /* LOCALITY = "dn=polardbx-storage-0-master" */  |
+----------+------------------------------------------------------------------------+
1 row in set