Permissions
Tags: opengauss
Published: 2023-04-04 01:38:26

A user who creates an object is the owner of this object. By default, separation of duties is disabled after database installation. A database system administrator has the same permissions as object owners. After an object is created, only the object owner or system administrator can query, modify, and delete the object, and grant permissions on the object to other users through GRANT by default.

To enable another user to use the object, grant required permissions to the user or the role that contains the user.

To remove permissions, use REVOKE. Object owners have implicit permissions (such as ALTER, DROP, COMMENT, INDEX, VACUUM, GRANT, and REVOKE) on objects. That is, once becoming the owner of an object, the owner is immediately granted the implicit permissions on the object. Object owners can remove their own common permissions, for example, making tables read-only to themselves or others, except the system administrator.

openGauss supports the following permissions, which are associated with different object types:

SELECT: allows SELECT on a specified table, view, or sequence. The SELECT permission on the corresponding column is also required for UPDATE or DELETE.

INSERT: allows INSERT on a specified table.

UPDATE: allows UPDATE on any column of a specified table. Generally, UPDATE also requires the SELECT permission to query which rows need to be updated. SELECT … FOR UPDATE and SELECT … FOR SHARE also require this permission on at least one column, in addition to the SELECT permission.

DELETE: allows DELETE on a row of a specified table. Generally, DELETE also requires the SELECT permission to query which rows need to be deleted.

TRUNCATE: allows TRUNCATE on a specified table.

REFERENCES: allows creation of a foreign key constraint. This permission is required on both referencing and referenced tables.

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 the CREATE permission on the schema of the object.
For tablespaces, allows tables to be created within the tablespace, and allows databases and schemas to be created that have the tablespace as their default tablespace.
CONNECT: allows you to access specified databases.

EXECUTE: allows you to use specified functions and the operators that are realized by the functions.

USAGE:

For procedural languages, allows use of the language for the creation of functions in that language.
For schemas, allows access to objects contained in the schema. Without this permission, it is still possible to see the object names.
For sequences, allows use of the nextval function.
For data sources, specifies access permissions or is used as ALL PRIVILEGES.
ALTER: allows users to modify the attributes of a specified object, excluding the owner and schema of the object.

DROP: allows users to delete a specified object.

COMMENT: allows users to define or modify comments of a specified object.

INDEX: allows users to create indexes on specified tables, manage indexes on the tables, and perform REINDEX and CLUSTER operations on the tables.

VACUUM: allows users to perform ANALYZE and VACUUM operations on specified tables.

ALL PRIVILEGES: grants all available permissions to specified users or roles at a time. Only a system administrator has the GRANT ALL PRIVILEGES permission.

Syntax
GRANT

GRANT grants permissions to roles and users. GRANT is used in the following scenarios:

Granting system permissions (such as sysadmin, CREATEDB, and CREATEROLE) to a role or user

The syntax for granting sysadmin permissions to a specified role is as follows:

""
GRANT ALL { PRIVILEGES | PRIVILEGE }
   TO role_name;
Granting the permissions of a role or user to others

The syntax for granting the permissions of a role to other others is as follows:

""
GRANT role_name [, ...]
   TO role_name [, ...]
   [ WITH ADMIN OPTION ];
Granting database object permissions to a role or user

Grant the table or view access permission to a user or role.

""
GRANT { { SELECT | INSERT | UPDATE | DELETE | TRUNCATE | REFERENCES | ALTER | DROP | COMMENT | INDEX | VACUUM } [, ...] 
      | ALL [ PRIVILEGES ] }
    ON { [ TABLE ] table_name [, ...]
       | ALL TABLES IN SCHEMA schema_name [, ...] }
    TO { [ GROUP ] role_name | PUBLIC } [, ...] 
    [ WITH GRANT OPTION ];
Grant the column access permission to a user or role.

""
GRANT { {{ SELECT | INSERT | UPDATE | REFERENCES | COMMENT } ( column_name [, ...] )} [, ...] 
      | ALL [ PRIVILEGES ] ( column_name [, ...] ) }
    ON [ TABLE ] table_name [, ...]
    TO { [ GROUP ] role_name | PUBLIC } [, ...]
    [ WITH GRANT OPTION ];
Grant the database access permission to a user or role.

""
GRANT { { CREATE | CONNECT | TEMPORARY | TEMP | ALTER | DROP | COMMENT } [, ...]
      | ALL [ PRIVILEGES ] }
    ON DATABASE database_name [, ...]
    TO { [ GROUP ] role_name | PUBLIC } [, ...]
    [ WITH GRANT OPTION ];
Grant the schema access permission to a user or role.

""
GRANT { { CREATE | USAGE | ALTER | DROP | COMMENT } [, ...] | ALL [ PRIVILEGES ] }
    ON SCHEMA schema_name [, ...]
    TO { [ GROUP ] role_name | PUBLIC } [, ...]
    [ WITH GRANT OPTION ];
 NOTE: When you grant table or view permissions to other users, you also need to grant the USAGE permission on the schema that the tables and views belong to. Without the USAGE permission, the users with table or view permissions can only see the object names, but cannot access them. This syntax cannot be used to grant the permission to create tables in schemas with the same name, but you can use the syntax for granting permission of a role to others to achieve the same effect.

Grant the tablespace access permission to a user or role.

""
GRANT { { CREATE | ALTER | DROP | COMMENT } [, ...] | ALL [ PRIVILEGES ] }
    ON TABLESPACE tablespace_name [, ...]
    TO { [ GROUP ] role_name | PUBLIC } [, ...]
    [ WITH GRANT OPTION ];
REVOKE

Revoking system permissions (such as sysadmin, CREATEDB, and CREATEROLE) from a role or user

Revoke the sysadmin permission from a role.

""
REVOKE ALL { PRIVILEGES | PRIVILEGE } FROM role_name;
Revoke the permissions of a role.

""
REVOKE [ ADMIN OPTION FOR ]
    role_name [, ...] FROM role_name [, ...]
    [ CASCADE | RESTRICT ];
Revoking permissions on database objects

Revoke the permission on a specified table or view.

""
REVOKE [ GRANT OPTION FOR ]
    { { SELECT | INSERT | UPDATE | DELETE | TRUNCATE | REFERENCES | ALTER | DROP | COMMENT | INDEX | VACUUM }[, ...] 
    | ALL [ PRIVILEGES ] }
    ON { [ TABLE ] table_name [, ...]
       | ALL TABLES IN SCHEMA schema_name [, ...] }
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT ];
Revoke the permission on a specified column in a table.

""
REVOKE [ GRANT OPTION FOR ]
    { {{ SELECT | INSERT | UPDATE | REFERENCES | COMMENT } ( column_name [, ...] )}[, ...] 
    | ALL [ PRIVILEGES ] ( column_name [, ...] ) }
    ON [ TABLE ] table_name [, ...]
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT ];
Revoke the permission on a specified database.

""
REVOKE [ GRANT OPTION FOR ]
    { { CREATE | CONNECT | TEMPORARY | TEMP | ALTER | DROP | COMMENT } [, ...] 
    | ALL [ PRIVILEGES ] }
    ON DATABASE database_name [, ...]
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT ];
Revoke the permission on a specified schema.

""
REVOKE [ GRANT OPTION FOR ]
    { { CREATE | USAGE | ALTER | DROP | COMMENT } [, ...] | ALL [ PRIVILEGES ] }
    ON SCHEMA schema_name [, ...]
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT ];
Revoke the permission on a specified tablespace.

""
REVOKE [ GRANT OPTION FOR ]
    { { CREATE | ALTER | DROP | COMMENT } [, ...] | ALL [ PRIVILEGES ] }
    ON TABLESPACE tablespace_name [, ...]
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT ];
Parameter Description
role_name

Specifies the username.

table_name

Specifies the table name.

column_name

Specifies the column name.

schema_name

Specifies the schema name.

database_name

Specifies the database name.

tablespace_name

Specifies the tablespace name.

WITH GRANT OPTION

If WITH GRANT OPTION is specified, the recipient of the permission can in turn grant it to others. Without a grant option, the recipient cannot do that. This option cannot be granted to PUBLIC.

Examples
Grant system permissions to a user or role.

Create the joe user and grant the sysadmin permission to it.

""
openGauss=# CREATE USER joe PASSWORD 'xxxxxxxx';
CREATE ROLE
openGauss=# GRANT ALL PRIVILEGES TO joe;
ALTER ROLE
Then the joe user has the sysadmin permission.

Grant object permissions to a user or role.

Create the test schema and the customer table.

""
openGauss=# CREATE SCHEMA test;
CREATE SCHEMA

openGauss=# CREATE TABLE customer
(
    c_customer_sk             integer,
    c_customer_id             char(5),
    c_first_name              char(6),
    c_last_name               char(8),
    Amount                    integer
);
CREATE TABLE
Revoke user joe's sysadmin permission, and grant it with the usage permission on the test schema and all the permissions on the customer table.

""
openGauss=# REVOKE ALL PRIVILEGES FROM joe;
ALTER ROLE
openGauss=# GRANT USAGE ON SCHEMA test TO joe;
GRANT
openGauss=# GRANT ALL PRIVILEGES ON customer TO joe;
GRANT
After the permissions are successfully granted, user joe has all the permissions on the customer table, including addition, deletion, modification, and query permissions.

Grant the query permission on the c_customer_sk, c_customer_id, and c_first_name columns and the update permission on the c_last_name column in the customer table to user joe.

""
openGauss=# GRANT select (c_customer_sk,c_customer_id,c_first_name),update (c_last_name) ON customer TO joe;
GRANT
After the permissions are successfully granted, user joe immediately has the query permission on the c_customer_sk, c_customer_id, c_first_name columns in the customer table. To enable user joe to grant these permissions to other users, execute the following statement:

""
openGauss=# GRANT select (c_customer_sk,c_customer_id,c_first_name) ON customer TO joe WITH GRANT OPTION;
GRANT
Grant the postgres database connection permission and schema creation permission to user joe and enable this user to grant these permissions to other users.

""
openGauss=# GRANT create,connect on database postgres TO joe WITH GRANT OPTION;
GRANT
Create the test_manager role, grant the access and object creation permissions on the test schema to the test_manager role, but do not allow this role to grant these permissions to others.

""
openGauss=# CREATE ROLE test_manager PASSWORD 'xxxxxxxx';
CREATE ROLE
openGauss=# GRANT USAGE,CREATE ON SCHEMA test TO test_manager;
GRANT
Create the tpcds_tbspc tablespace and grant all permissions on the tablespace to user joe. However, user joe cannot grant these permissions to other users.

""
openGauss=# CREATE TABLESPACE tpcds_tbspc RELATIVE LOCATION 'tablespace/tablespace_1';
CREATE TABLESPACE
openGauss=# GRANT ALL ON TABLESPACE tpcds_tbspc TO joe;
GRANT
Grant a user's or role's permissions to other users or roles

Create the manager role, grant joe's permissions to the manager role, and allow the manager role to grant these permissions to others.

""
openGauss=# CREATE ROLE manager PASSWORD 'xxxxxxxx';
CREATE ROLE
openGauss=# GRANT joe TO manager WITH ADMIN OPTION;
GRANT ROLE
Create the senior_manager user and grant manager's permissions to it.

""
openGauss=# CREATE ROLE senior_manager PASSWORD 'xxxxxxxx';
CREATE ROLE
openGauss=# GRANT manager TO senior_manager;
GRANT ROLE