distributed-database-middleware/umn/source/schema_management/creating_a_schema.rst

original_name

ddm_06_0006.html

Creating a Schema

Prerequisites

• You have logged in to the DDM console.

• The DDM instance is in the Running state.

• Do not modify or delete the internal accounts (DDMRW*, DDMR*, and DDMREP*) created on data nodes. Otherwise, services will be affected.

  Note

  • The internal account name is in the format: Fixed prefix (such as DDMRW, DDMR, or DDMREP) + Hash value of the data node ID.
  • A random password is generated, which contains 16 to 32 characters.
  • All DB instances associated with one schema must have the same major MySQL version.
  • Multiple schemas can be created in a DDM instance and associated with the same data node. One DDM instance can be associated with either RDS for MySQL or GaussDB(for MySQL) instances, but not both.
  • One data node cannot be associated with schemas in different DDM instances.
  • If you select Sharded for Sharding when you create a schema, the shard name follows the rule: schema+xxxx. xxxx indicates the digit increased from 0000. For example, if a schema name is db_cbb5 and the total number of shards is 2, the shard names are db_cbb5_0000 and db_cbb5_0001.
  • Read-only DB instances cannot be associated with the schema as data nodes.

You can create a schema in two ways: on the Instances page or on the Schemas page. This section uses the Instances page as an example to describe how to create a schema.

Procedure

1. In the navigation pane, choose Instances. In the instance list, locate the DDM instance that you want to create a schema for and click Create Schema in the Operation column.

2. On the displayed page, specify a sharding mode, enter a schema name, set the number of shards, select the required DDM accounts, and click Next.

3. Enter a database account with the required permissions and click Test Connection.

   Note

   Required permissions: SELECT, INSERT, UPDATE, DELETE, CREATE, DROP, RELOAD, PROCESS, REFERENCES, INDEX, ALTER, SHOW DATABASES, CREATE TEMPORARY TABLES, LOCK TABLES, EXECUTE, REPLICATION SLAVE, REPLICATION CLIENT, CREATE VIEW, SHOW VIEW, CREATE ROUTINE, ALTER ROUTINE, CREATE USER, EVENT, TRIGGER WITH GRANT OPTION

   Create a special account and assign it the above permissions as required. Then use the account to create a schema for later operations.

4. After the test becomes successful, click Finish.