Postgres和MySQL创建用户并授予db权限

Postgresql和MySQL还是有很多不同的。就比如授权来说。当下有个业务场景，我们的报表数据库需要根据业务划分不同的db，然后创建对应的user。

如果是MySQL, 可以这样做

mysql> create database mydb;
mysql> create user a_user identified by 'ThePassword'
    -> ;
Query OK, 0 rows affected (0.04 sec)

mysql> grant all privileges on mydb.* to a_user@'%';
Query OK, 0 rows affected (0.02 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)

对于Postgres9.0以上

创建一个用户etl_user，允许登陆，永不过期

create role etl_user login password 'ThePassowrd' valid until 'infinity';

将db权限授予user

grant all privileges on database mydb to etl_user ;

或者，分别授权

GRANT CONNECT ON DATABASE mydb TO etl_user;
GRANT USAGE ON SCHEMA public TO etl_user;
GRANT ALL PRIVILEGES ON ALL TABLES IN SCHEMA public TO etl_user;
GRANT ALL PRIVILEGES ON ALL SEQUENCES IN SCHEMA public TO etl_user;

这时候，如果你要删除这个role，则必须先要删除关联的privileges

REVOKE CONNECT ON DATABASE mydb FROM etl_user;
REVOKE ALL PRIVILEGES ON ALL TABLES IN SCHEMA public FROM etl_user;
REVOKE ALL PRIVILEGES ON ALL SEQUENCES IN SCHEMA public FROM etl_user;
REVOKE ALL PRIVILEGES ON ALL FUNCTIONS IN SCHEMA public FROM etl_user;
DROP USER etl_user;