GRANT

Defines access privileges.

Synopsis

GRANT { {SELECT | INSERT | UPDATE | DELETE | REFERENCES | 
TRIGGER | TRUNCATE } [,...] | ALL [PRIVILEGES] }
    ON [TABLE] <tablename> [, ...]
    TO {<rolename> | PUBLIC} [, ...] [WITH GRANT OPTION]

GRANT { {USAGE | SELECT | UPDATE} [,...] | ALL [PRIVILEGES] }
    ON SEQUENCE <sequencename> [, ...]
    TO { <rolename> | PUBLIC } [, ...] [WITH GRANT OPTION]

GRANT { {CREATE | CONNECT | TEMPORARY | TEMP} [,...] | ALL 
[PRIVILEGES] }
    ON DATABASE <dbname> [, ...]
    TO {<rolename> | PUBLIC} [, ...] [WITH GRANT OPTION]

GRANT { USAGE | ALL [ PRIVILEGES ] }
    ON FOREIGN DATA WRAPPER <fdwname> [, ...]
    TO { [ GROUP ] <rolename> | PUBLIC } [, ...] [ WITH GRANT OPTION ]

GRANT { USAGE | ALL [ PRIVILEGES ] }
    ON FOREIGN SERVER <servername> [, ...]
    TO { [ GROUP ] <rolename> | PUBLIC } [, ...] [ WITH GRANT OPTION ]

GRANT { EXECUTE | ALL [PRIVILEGES] }
    ON FUNCTION <funcname> ( [ [<argmode>] [<argname>] <argtype> [, ...] 
] ) [, ...]
    TO {<rolename> | PUBLIC} [, ...] [WITH GRANT OPTION]

GRANT { USAGE | ALL [PRIVILEGES] }
    ON LANGUAGE <langname> [, ...]
    TO {<rolename> | PUBLIC} [, ...] [WITH GRANT OPTION]

GRANT { {CREATE | USAGE} [,...] | ALL [PRIVILEGES] }
    ON SCHEMA <schemaname> [, ...]
    TO {<rolename> | PUBLIC} [, ...] [WITH GRANT OPTION]

GRANT { CREATE | ALL [PRIVILEGES] }
    ON TABLESPACE <tablespacename> [, ...]
    TO {<rolename> | PUBLIC} [, ...] [WITH GRANT OPTION]

GRANT <parent_role> [, ...] 
    TO <member_role> [, ...] [WITH ADMIN OPTION]

GRANT { SELECT | INSERT | ALL [PRIVILEGES] } 
    ON PROTOCOL <protocolname>
    TO <username>

Description

The GRANT command has two basic variants: one that grants privileges on a database object (table, view, foreign table, sequence, database, foreign-data wrapper, foreign server, function, procedural language, schema, or tablespace), and one that grants membership in a role.

GRANT on Database Objects

This variant of the GRANT command gives specific privileges on a database object to one or more roles. These privileges are added to those already granted, if any.

The key word PUBLIC indicates that the privileges are to be granted to all roles, including those that may be created later. PUBLIC may be thought of as an implicitly defined group-level role that always includes all roles. Any particular role will have the sum of privileges granted directly to it, privileges granted to any role it is presently a member of, and privileges granted to PUBLIC.

If WITH GRANT OPTION is specified, the recipient of the privilege may in turn grant it to others. Without a grant option, the recipient cannot do that. Grant options cannot be granted to PUBLIC.

There is no need to grant privileges to the owner of an object (usually the role that created it), as the owner has all privileges by default. The right to drop an object, or to alter its definition in any way is not described by a grantable privilege; it is inherent in the owner, and cannot be granted or revoked. The owner implicitly has all grant options for the object, too.

Depending on the type of object, the initial default privileges may include granting some privileges to PUBLIC. The default is no public access for tables, schemas, and tablespaces; CONNECT privilege and TEMP table creation privilege for databases; EXECUTE privilege for functions; and USAGE privilege for languages. The object owner may of course revoke these privileges.

GRANT on Roles

This variant of the GRANT command grants membership in a role to one or more other roles. Membership in a role is significant because it conveys the privileges granted to a role to each of its members.

If WITH ADMIN OPTION is specified, the member may in turn grant membership in the role to others, and revoke membership in the role as well. Database superusers can grant or revoke membership in any role to anyone. Roles having CREATEROLE privilege can grant or revoke membership in any role that is not a superuser.

Unlike the case with privileges, membership in a role cannot be granted to PUBLIC.

GRANT on Protocols

After creating a custom protocol, specify CREATE TRUSTED PROTOCOL to be able to allow any user besides the owner to access it. If the protocol is not trusted, you cannot give any other user permission to use it to read or write data. After a TRUSTED protocol is created, you can specify which other users can access it with the GRANT command.

To allow a user to create a readable external table with a trusted protocol
```
GRANT SELECT ON PROTOCOL <protocolname> TO <username>
```
To allow a user to create a writable external table with a trusted protocol
```
GRANT INSERT ON PROTOCOL <protocolname> TO <username>
```
To allow a user to create both readable and writable external tables with a trusted protocol
```
GRANT ALL ON PROTOCOL <protocolname> TO <username>
```

You can also use this command to grant users permissions to create and use hdfs, s3, and pxf external tables. However, external tables of type http, https, gpfdist, and gpfdists, are implemented internally in Greenplum Database instead of as custom protocols. For these types, use the CREATE ROLE or ALTER ROLE command to set the CREATEEXTTABLE or NOCREATEEXTTABLE attribute for each user. See CREATE ROLE for syntax and examples.

Parameters

SELECT

Allows SELECT from any column of the specified table, view, or sequence. Also allows the use of COPY TO.

INSERT

Allows INSERT of a new row into the specified table. Also allows COPY FROM.

UPDATE

Allows UPDATE of any column of the specified table. SELECT ... FOR UPDATE and SELECT ... FOR SHARE also require this privilege (as well as the SELECT privilege). For sequences, this privilege allows the use of the nextval() and setval() functions.

DELETE

Allows DELETE of a row from the specified table.

REFERENCES

This keyword is accepted, although foreign key constraints are currently not supported in Greenplum Database. To create a foreign key constraint, it is necessary to have this privilege on both the referencing and referenced tables.

TRIGGER

Allows the creation of a trigger on the specified table.

Note: Greenplum Database does not support triggers.

TRUNCATE

Allows TRUNCATE of all rows from the specified table.

CREATE

For databases, allows new schemas to be created within the database.

For schemas, allows new objects to be created within the schema. To rename an existing object, you must own the object and have this privilege for the containing schema.

For tablespaces, allows tables and indexes to be created within the tablespace, and allows databases to be created that have the tablespace as their default tablespace. (Note that revoking this privilege will not alter the placement of existing objects.)

CONNECT

Allows the user to connect to the specified database. This privilege is checked at connection startup (in addition to checking any restrictions imposed by pg_hba.conf).

TEMPORARY

TEMP

Allows temporary tables to be created while using the database.

EXECUTE

Allows the use of the specified function and the use of any operators that are implemented on top of the function. This is the only type of privilege that is applicable to functions. (This syntax works for aggregate functions, as well.)

USAGE

For procedural languages, allows the use of the specified language for the creation of functions in that language. This is the only type of privilege that is applicable to procedural languages.

For schemas, allows access to objects contained in the specified schema (assuming that the objects' own privilege requirements are also met). Essentially this allows the grantee to look up objects within the schema.

For sequences, this privilege allows the use of the nextval() function.

For foreign-data wrappers, this privilege enables the grantee to create new servers using that foreign-data wrapper.

For servers, this privilege enables the grantee to create, alter, and drop their own user's user mappings associated with that server. Also, it enables the grantee to query the options of the server and associated user mappings.

ALL PRIVILEGES

Grant all of the available privileges at once. The PRIVILEGES key word is optional in Greenplum Database, though it is required by strict SQL.

PUBLIC

A special group-level role that denotes that the privileges are to be granted to all roles, including those that may be created later.

WITH GRANT OPTION

The recipient of the privilege may in turn grant it to others.

WITH ADMIN OPTION

The member of a role may in turn grant membership in the role to others.

Notes

Database superusers can access all objects regardless of object privilege settings. One exception to this rule is view objects. Access to tables referenced in the view is determined by permissions of the view owner not the current user (even if the current user is a superuser).

If a superuser chooses to issue a GRANT or REVOKE command, the command is performed as though it were issued by the owner of the affected object. In particular, privileges granted via such a command will appear to have been granted by the object owner. For role membership, the membership appears to have been granted by the containing role itself.

GRANT and REVOKE can also be done by a role that is not the owner of the affected object, but is a member of the role that owns the object, or is a member of a role that holds privileges WITH GRANT OPTION on the object. In this case the privileges will be recorded as having been granted by the role that actually owns the object or holds the privileges WITH GRANT OPTION.

Granting permission on a table does not automatically extend permissions to any sequences used by the table, including sequences tied to SERIAL columns. Permissions on a sequence must be set separately.

Greenplum Database does not support granting or revoking privileges for individual columns of a table. One possible workaround is to create a view having just the desired columns and then grant privileges to that view.

The GRANT command cannot be used to set privileges for the protocols file, gpfdist, or gpfdists. These protocols are implemented internally in Greenplum Database. Instead, use the CREATE ROLE or ALTER ROLE command to set the CREATEEXTTABLE attribute for the role.

Use psql's \z meta-command to obtain information about existing privileges for an object.

Examples

Grant insert privilege to all roles on table mytable:

GRANT INSERT ON mytable TO PUBLIC;

Grant all available privileges to role sally on the view topten. Note that while the above will indeed grant all privileges if executed by a superuser or the owner of topten, when executed by someone else it will only grant those permissions for which the granting role has grant options.

GRANT ALL PRIVILEGES ON topten TO sally;

Grant membership in role admins to user joe:

GRANT admins TO joe;

Compatibility

The PRIVILEGES key word in is required in the SQL standard, but optional in Greenplum Database. The SQL standard does not support setting the privileges on more than one object per command.

Greenplum Database allows an object owner to revoke their own ordinary privileges: for example, a table owner can make the table read-only to themselves by revoking their own INSERT, UPDATE, DELETE, and TRUNCATE privileges. This is not possible according to the SQL standard. Greenplum Database treats the owner's privileges as having been granted by the owner to themselves; therefore the owner can revoke them too. In the SQL standard, the owner's privileges are granted by an assumed system entity.

The SQL standard allows setting privileges for individual columns within a table.

The SQL standard provides for a USAGE privilege on other kinds of objects: character sets, collations, translations, domains.

Privileges on databases, tablespaces, schemas, and languages are Greenplum Database extensions.