The `USAGE` Privilege

To be able to use metadata objects other than tables, views, stored procedures or functions, triggers and packages, it is necessary to grant the user (or database object like trigger, procedure or function) the USAGE privilege on these objects.

By default, Firebird executes PSQL modules with the privileges of the caller, so it is necessary that either the user or otherwise the routine itself has been granted the USAGE privilege.This can be changed with the SQL SECURITY clause of the DDL statements of those objects.

Note	The `USAGE` privilege is currently only available for exceptions and sequences (in `gen_id(gen_name, n)` or `next value for gen_name`).Support for the `USAGE` privilege for other metadata objects may be added in future releases.

Note

For sequences (generators), the USAGE privilege only grants the right to increment the sequence using the GEN_ID function or NEXT VALUE FOR.The SET GENERATOR statement is a synonym for ALTER SEQUENCE … RESTART WITH …, and is considered a DDL statement.By default, only the owner of the sequence and administrators have the rights to such operations.The right to set the initial value of any sequence can be granted with GRANT ALTER ANY SEQUENCE, which is not recommend for general users.

Examples of Granting the `USAGE` Privilege

Granting the USAGE privilege on a sequence to a role:
```
GRANT USAGE ON SEQUENCE GEN_AGE
  TO ROLE MANAGER;
```

Granting the USAGE privilege on a sequence to a trigger:

GRANT USAGE ON SEQUENCE GEN_AGE
  TO TRIGGER TR_AGE_BI;

Granting the USAGE privilege on an exception to a package:
```
GRANT USAGE ON EXCEPTION
  TO PACKAGE PKG_BILL;
```

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DDL Privileges

By default, only administrators can create new metadata objects.Altering or dropping these objects is restricted to the owner of the object (its creator) and administrators.DDL privileges can be used to grant privileges for these operations to other users.

Available DDL Privileges

CREATE: Allows creation of an object of the specified type
ALTER ANY: Allows modification of any object of the specified type
DROP ANY: Allows deletion of any object of the specified type
ALL [PRIVILEGES]: Combines the CREATE, ALTER ANY and DROP ANY privileges for the specified type

Note	There are no separate DDL privileges for triggers and indexes.The necessary privileges are inherited from the table or view.Creating, altering or dropping a trigger or index requires the `ALTER ANY TABLE` or `ALTER ANY VIEW` privilege.

Examples of Granting DDL Privileges

Allow user JOE to create tables
```
GRANT CREATE TABLE
  TO USER Joe;
```

Allow user JOE to alter any procedure

GRANT ALTER ANY PROCEDURE
  TO USER Joe;

Database DDL Privileges

The syntax for granting privileges to create, alter or drop a database deviates from the normal syntax of granting DDL privileges for other object types.

Available Database DDL Privileges

CREATE: Allows creation of a database
ALTER: Allows modification of the current database
DROP: Allows deletion of the current database
ALL [PRIVILEGES]: Combines the ALTER and DROP privileges.ALL does not include the CREATE privilege.

The ALTER DATABASE and DROP DATABASE privileges apply only to the current database, whereas DDL privileges ALTER ANY and DROP ANY on other object types apply to all objects of the specified type in the current database.The privilege to alter or drop the current database can only be granted by administrators.

The CREATE DATABASE privilege is a special kind of privilege as it is saved in the security database.A list of users with the CREATE DATABASE privilege is available from the virtual table SEC$DB_CREATORS.Only administrators in the security database can grant the privilege to create a new database.

Note	`SCHEMA` is currently a synonym for `DATABASE`;this may change in a future version, so we recommend to always use `DATABASE`

Examples of Granting Database DDL Privileges

Granting SUPERUSER the privilege to create databases:
```
GRANT CREATE DATABASE
  TO USER Superuser;
```
Granting JOE the privilege to execute ALTER DATABASE for the current database:
```
GRANT ALTER DATABASE
  TO USER Joe;
```
Granting FEDOR the privilege to drop the current database:
```
GRANT DROP DATABASE
  TO USER Fedor;
```

The USAGE Privilege