CREATE DATABASE
Creates a new database.
CREATE DATABASE [IF NOT EXISTS] db_name [ON CLUSTER cluster] [ENGINE = engine(...)] [COMMENT 'Comment']
Clausesβ
IF NOT EXISTSβ
If the db_name
database already exists, then ClickHouse does not create a new database and:
- Doesnβt throw an exception if clause is specified.
- Throws an exception if clause isnβt specified.
ON CLUSTERβ
ClickHouse creates the db_name
database on all the servers of a specified cluster. More details in a Distributed DDL article.
ENGINEβ
By default, ClickHouse uses its own Atomic database engine. There are also Lazy, MySQL, PostgresSQL, MaterializedMySQL, MaterializedPostgreSQL, Replicated, SQLite.
COMMENTβ
You can add a comment to the database when you creating it.
The comment is supported for all database engines.
Syntax
CREATE DATABASE db_name ENGINE = engine(...) COMMENT 'Comment'
Example
Query:
CREATE DATABASE db_comment ENGINE = Memory COMMENT 'The temporary database';
SELECT name, comment FROM system.databases WHERE name = 'db_comment';
Result:
ββnameββββββββ¬βcommentβββββββββββββββββ
β db_comment β The temporary database β
ββββββββββββββ΄βββββββββββββββββββββββββ