[Yandex Cloud documentation](../../index.md) > [Yandex Managed Service for PostgreSQL](../index.md) > [Concepts](index.md) > SQL command limits

# SQL command limits

Managed Service for PostgreSQL has some limitations on DB owner actions when using SQL commands:

* You cannot change the PostgreSQL settings.
* You cannot manage users or create and assign roles to them. However, you can [grant user privileges](../operations/grant.md) at the level of individual DB objects.
* You cannot create databases; However, database owners and users with the `mdb_admin` [role](roles.md) can run the `ALTER DATABASE` command for a previously created database.
* You cannot connect to the `postgres` system database.
* You cannot request the `postgres` user password and connect to the database on their behalf.
* You cannot manage PostgreSQL extensions.
* No actions that require superuser privileges are allowed.

You can, however, perform all these actions using the Yandex Cloud tools. To learn how, check out our [step-by-step guides](../operations/index.md).