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<div>
<h2 class="title">
<a name="accesscontrol-chapt"></a>Chapter&nbsp;6.&nbsp;Access Control</h2>
</div>
<div>
<div class="authorgroup">
<div class="author">
<h3 class="author">
<span class="firstname">Fred</span> <span class="surname">Toussi</span>
</h3>
<div class="affiliation">
<span class="orgname">The HSQL Development Group<br>
</span>
</div>
</div>
</div>
</div>
<div>
<p class="releaseinfo">$Revision: 3096 $</p>
</div>
<div>
<div class="legalnotice">
<a name="N1170F"></a>
<p>Copyright 2010 Fred Toussi. Permission is granted to distribute
this document without any alteration under the terms of the HSQLDB
license. Additional permission is granted to the HSQL Development Group
to distribute this document with or without alterations under the terms
of the HSQLDB license.</p>
</div>
</div>
<div>
<p class="pubdate">$Date: 2009-08-09 17:50:39 +0100 (Sun, 09 Aug 2009) $</p>
</div>
</div>
</div>
<div class="toc">
<p>
<b>Table of Contents</b>
</p>
<dl>
<dt>
<span class="section"><a href="accesscontrol-chapt.html#N11712">Overview</a></span>
</dt>
<dt>
<span class="section"><a href="accesscontrol-chapt.html#N11752">Authorizations and Access Control</a></span>
</dt>
<dd>
<dl>
<dt>
<span class="section"><a href="accesscontrol-chapt.html#N11775">Built-In Roles and Users</a></span>
</dt>
<dt>
<span class="section"><a href="accesscontrol-chapt.html#N117CE">Access Rights</a></span>
</dt>
</dl>
</dd>
<dt>
<span class="section"><a href="accesscontrol-chapt.html#N11810">Statements for
Authorization and Access Control</a></span>
</dt>
</dl>
</div>
<div class="section" lang="en">
<div class="titlepage">
<div>
<div>
<h2 class="title" style="clear: both">
<a name="N11712"></a>Overview</h2>
</div>
</div>
</div>
<p>Apart from schemas and their object, each HyperSQL catalog has USER
and ROLE objects. These objects are collectively called
<span class="emphasis"><em>authorizations</em></span>. Each AUTHORIZATION has some access
rights on some of the schemas or the objects they contain. The persistent
elements of an SQL environment are database objects</p>
<p>Each database object has a name. A name is an identifier and is
unique within its name-space. Authorizations names follow the rules
described below and the case-normal form is stored in the database. When
connecting to a database, the user name and password must match the case
of the case-normal form.</p>
<a name="N1171C" class="indexterm"></a>
<p>
<span class="bold"><strong>identifier</strong></span>
</p>
<p>
<span class="emphasis"><em>definition of identifier</em></span>
</p>
<p>
<code class="literal">&lt;identifier&gt; ::= &lt;regular identifier&gt; |
&lt;delimited identifier&gt; | &lt;SQL language identifier&gt;
</code>
</p>
<p>
<code class="literal">&lt;delimited identifier&gt; ::= &lt;double quote&gt;
&lt;character sequence&gt; &lt;double quote&gt;</code>
</p>
<p>
<code class="literal">&lt;regular identifier&gt; ::= &lt;special character
sequence&gt;</code>
</p>
<p>
<code class="literal">&lt;SQL language identifier&gt; ::= &lt;special
character sequence&gt;</code>
</p>
<p>A <code class="literal">&lt;delimited identifier&gt;</code> is a sequence
of characters enclosed with double-quote symbols. All characters are
allowed in the character sequence.</p>
<p>A <code class="literal">&lt;regular identifier&gt;</code> is a special
sequence of characters. It consists of letters, digits and the underscore
characters. It must begin with a letter.</p>
<p>A <code class="literal">&lt;SQL language identifier&gt;</code> is similar
to <code class="literal">&lt;regular identifier&gt;</code> but the letters can range
only from A-Z in the ASCII character set. This type of identifier is used
for names of CHARACTER SET objects.</p>
<p>If the character sequence of a delimited identifier is the same
as an undelimited identifier, it represents the same identifier. For
example "JOHN" is the same identifier as JOHN. In a <code class="literal">&lt;regular
identifier&gt;</code> the case-normal form is considered for
comparison. This form consists of the upper-case of equivalent of all the
letters.</p>
<p>The character sequence length of all identifiers must be between
1 and 128 characters.</p>
<p>A reserved word is one that is used by the SQL Standard for
special purposes. It is similar to a <code class="literal">&lt;regular
identifier&gt;</code> but it cannot be used as an identifier for user
objects. If a reserved word is enclosed in double quote characters, it
becomes a quoted identifier and can be used for database
objects.</p>
</div>
<div class="section" lang="en">
<div class="titlepage">
<div>
<div>
<h2 class="title" style="clear: both">
<a name="N11752"></a>Authorizations and Access Control</h2>
</div>
</div>
</div>
<p>In general, ROLE and USER objects simply control access to schema
objects. This is the scope of the SQL Standard. However, there are special
roles that allow the creation of USER and ROLE objects and also allow some
special operations on the database as a whole. These roles are not defined
by the Standard, which has left it to implementors to define such roles as
they are needed for the particular SQL implementation.</p>
<p>A ROLE has a name a collection of zero or more other roles, plus
some privileges (access rights). A USER has a name and a password. It
similarly has a collection of zero or more roles plus some
privileges.</p>
<p>USER objects existed in the SQL-92, but ROLE objects were introduced
in SQL:1999. Originally it was intended that USER objects would normally
be the same as the operating system USER objects and their authentication
would be handled outside the SQL environment. The co-existence of ROLE and
USER objects results in complexity. With the addition of ROLE objects,
there is no rationale, other than legacy support, for granting privileges
to USER objects directly. It is better to create roles and grant
privileges to them, then grant the roles to USER objects.</p>
<p>The Standard effectively defines a special ROLE, named PUBLIC. All
authorization have the PUBLIC role, which cannot be removed from them.
Therefore any access right assigned to the PUBLIC role applies to all
authorizations in the database. For many simple databases, it is adequate
to create a single, non-admin user, then assign access rights to the
pre-existing PUBLIC role. Access to INFORMATION_SCHEMA views is granted to
PUBLIC, therefore these views are accessible to all. However, the contents
of each view depends on the ROLE or USER (AUTHORIZATION) that is in force
while accessing the view.</p>
<p>Each schema has a single AUTHORIZATION. This is commonly known as
the <span class="emphasis"><em>owner</em></span> of the schema. All the objects in the
schema inherit the schema owner. The schema owner can add objects to the
schema, drop them or alter them.</p>
<p>By default, the objects in a schema can only be accessed by the
schema owner. The schema owner can grant access rights on the objects to
other users or roles.</p>
<a name="N11764" class="indexterm"></a>
<p>
<span class="bold"><strong>authorization
identifier</strong></span>
</p>
<p>
<span class="emphasis"><em>authorization identifier</em></span>
</p>
<p>
<code class="literal">&lt;authorization identifier&gt; ::= &lt;role name&gt; |
&lt;user name&gt;</code>
</p>
<p>Authorization identifiers share the same name-space within the
database. The same name cannot be used for a USER and a ROLE.</p>
<div class="section" lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="N11775"></a>Built-In Roles and Users</h3>
</div>
</div>
</div>
<p>There are some pre-defined roles in each database; some defined by
the SQL Standard, some by HyperSQL. These roles can be assigned to users
(directly or via other, user-defined roles). In addition, there is the
default initial user, SA, created with each new database.</p>
<a name="N1177A" class="indexterm"></a>
<p>
<span class="bold"><strong>PUBLIC</strong></span>
</p>
<p>
<span class="emphasis"><em>the PUBLIC role</em></span>
</p>
<p>The role that is assigned to all authorizations (roles and
users) in the database. This role has access rights to all objects in
the INFORMATION_SCHEMA. Any roles or rights granted to this role, are in
effect granted to all users of the database.</p>
<a name="N11788" class="indexterm"></a>
<p>
<span class="bold"><strong>_SYSTEM</strong></span>
</p>
<p>
<span class="emphasis"><em>the _SYSTEM role</em></span>
</p>
<p>This role is the authorization for the pre-defined (system)
objects in the database, including the INFORMATION_SCHEMA. This role
cannot be assigned to any authorization.</p>
<a name="N11796" class="indexterm"></a>
<p>
<span class="bold"><strong>DBA</strong></span>
</p>
<p>
<span class="emphasis"><em>the DBA role (HyperSQL-specific)</em></span>
</p>
<p>This is a special role in HyperSQL. A user that has this role
can perform all possible administrative tasks on the database. The DBA
role can also act as a proxy for all the roles and users in the
database. This means it can do everything the authorization for a schema
can do, including dropping the schema or its objects, or granting rights
on the schema objects to a grantee.</p>
<a name="N117A4" class="indexterm"></a>
<p>
<span class="bold"><strong>CREATE_SCHEMA</strong></span>
</p>
<p>
<span class="emphasis"><em>the CREATE_SCHEMA role
(HyperSQL-specific)</em></span>
</p>
<p>An authorization that has this role, can create schemas. The
DBA authorization has this role and can grant it to other
authorizations.</p>
<a name="N117B2" class="indexterm"></a>
<p>
<span class="bold"><strong>CHANGE_AUTHORIZATION</strong></span>
</p>
<p>
<span class="emphasis"><em>the CHANGE_AUTHORIZATION role
(HyperSQL-specific)</em></span>
</p>
<p>A user that has this role, can change the authorization for the
current session to another user. The DBA authorization has this role and
can grant it to other authorizations.</p>
<a name="N117C0" class="indexterm"></a>
<p>
<span class="bold"><strong>SA</strong></span>
</p>
<p>
<span class="emphasis"><em>the SA user (HyperSQL-specific)</em></span>
</p>
<p>This user is automatically created with a new database and has
the DBA role. Initially, the password for this user is an empty string.
After connecting to the new database as this user, it is possible to
change the password, create other users and created new schema objects.
The SA user can be dropped by another user that has the DBA
role.</p>
</div>
<div class="section" lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="N117CE"></a>Access Rights</h3>
</div>
</div>
</div>
<p>By default, the objects in a schema can only be accessed by the
schema owner. But the schema owner can grant privileges (access rights)
on the objects to other users or roles.</p>
<p>Things can get far more complex, because the grant of privileges
can be made WITH GRANT OPTION. In this case, the role or user that has
been granted the privilege can grant the privilege to other roles and
users.</p>
<p>Privileges can also be revoked from users or roles.</p>
<p>The statements for granting and revoking privileges normally
specify which privileges are granted or revoked. However, there is a
shortcut, ALL PRIVILEGES, which means all the privileges that the
<code class="literal">&lt;grantor&gt;</code> has on the schema object. The
<code class="literal">&lt;grantor&gt;</code> is normally the CURRENT_USER of the
session that issues the statement.</p>
<p>The user or role that is granted privileges is referred to as
<code class="literal">&lt;grantee&gt;</code> for the granted privileges.</p>
<p>
<span class="bold"><strong>Table</strong></span>
</p>
<p>For tables, including views, privileges can be granted with
different degrees of granularity. It is possible to grant a privilege on
all columns of a table, or on specific columns of the table.</p>
<p>The DELETE privilege applies to the table, rather than its
columns. It applies to all DELETE statements.</p>
<p>The SELECT, INSERT and UPDATE privileges may apply to all
columns or to individual columns. These privileges determine whether the
<code class="literal">&lt;grantee&gt;</code> can execute SQL data statements on
the table.</p>
<p>The SELECT privilege designates the columns that can be
referenced in SELECT statements, as well as the columns that are read in
a DELETE or UPDATE statement, including the search condition.</p>
<p>The INSERT privilege designates the columns into which explicit
values can be inserted. To be able to insert a row into the table, the
user must therefore have the INSERT privilege on the table, or at least
all the columns that do not have a default value.</p>
<p>The UPDATE privilege simply designates the table or the
specific columns that can be updated.</p>
<p>The REFERENCES privilege allows the
<code class="literal">&lt;grantee&gt;</code> to define a FOREIGN KEY constraint on
a different table, which references the table or the specific columns
designated for the REFERENCES privilege.</p>
<p>The TRIGGER privilege allows adding a trigger to the
table.</p>
<p>
<span class="bold"><strong>Sequence, Type, Domain, Character Set,
Collation, Transliteration,</strong></span>
</p>
<p>For these objects, only USAGE can be granted. The USAGE
privilege is needed when object is referenced directly in an SQL
statement.</p>
<p>
<span class="bold"><strong>Routine</strong></span>
</p>
<p>For routines, including procedures or functions, only EXECUTE
privilege can be granted. This privilege is needed when the routine is
used directly in an SQL statement.</p>
<p>
<span class="bold"><strong>Other Objects</strong></span>
</p>
<p>Other objects such as constraints and assertions are not used
directly and there is no grantable privilege that refers to
them.</p>
</div>
</div>
<div class="section" lang="en">
<div class="titlepage">
<div>
<div>
<h2 class="title" style="clear: both">
<a name="N11810"></a>Statements for
Authorization and Access Control</h2>
</div>
</div>
</div>
<p>The statements listed below allow creation and destruction of USER
and ROLE objects. The GRANT and REVOKE statements allow roles to be
assigned to other roles or to users. The same statements are also used in
a different form to assign privileges on schema objects to users and
roles.</p>
<a name="N11816" class="indexterm"></a>
<p>
<a name="create_user-sql"></a><span class="bold"><strong>CREATE
USER</strong></span>
</p>
<p>
<span class="emphasis"><em>user definition (HyperSQL)</em></span>
</p>
<p>
<code class="literal">&lt;user definition&gt; ::= CREATE USER &lt;user
name&gt; PASSWORD &lt;password&gt; [ ADMIN ]</code>
</p>
<p>Define a new user and its password. <code class="literal">&lt;user
name&gt;</code> is an SQL identifier. If it is double-quoted it is
case-sensitive, otherwise it is turned to uppercase.
<code class="literal">&lt;password&gt;</code> is a string enclosed with single quote
characters and is case-sensitive. If <code class="literal">ADMIN</code> is
specified, the DBA role is granted to the new user. Only a user with the
DBA role can execute this statement.</p>
<a name="N11831" class="indexterm"></a>
<p>
<span class="bold"><strong>DROP USER</strong></span>
</p>
<p>
<span class="emphasis"><em>drop user statement (HyperSQL)</em></span>
</p>
<p>
<code class="literal">&lt;drop user statement&gt; ::= DROP USER &lt;user
name&gt;</code>
</p>
<p>Drop (destroy) an existing user. If the specified user is the
authorization for a schema, the schema is destroyed. Only a user with the
DBA role can execute this statement.</p>
<a name="N11842" class="indexterm"></a>
<p>
<span class="bold"><strong>ALTER USER ... SET
PASSWORD</strong></span>
</p>
<p>
<span class="emphasis"><em>set the password for a user
(HyperSQL)</em></span>
</p>
<p>
<code class="literal">&lt;alter user set password statement&gt; ::= ALTER USER
&lt;user name&gt; SET PASSWORD &lt;password&gt;</code>
</p>
<p>Change the password of an existing user. <code class="literal">&lt;user
name&gt;</code> is an SQL identifier. If it is double-quoted it is
case-sensitive, otherwise it is turned to uppercase.
<code class="literal">&lt;password&gt;</code> is a string enclosed with single quote
characters and is case-sensitive. Only a user with the DBA role can
execute this command.</p>
<a name="N11859" class="indexterm"></a>
<p>
<span class="bold"><strong>ALTER USER ... SET INITIAL
SCHEMA</strong></span>
</p>
<p>
<span class="emphasis"><em>set the initial schema for a user
(HyperSQL)</em></span>
</p>
<p>
<code class="literal">&lt;alter user set initial schema statement&gt; ::=
ALTER USER &lt;user name&gt; SET INITIAL SCHEMA &lt;schema name&gt; |
DEFAULT</code>
</p>
<p>Change the initial schema for a user. The initial schema is the
schema used by default for SQL statements issued during a session. If
<code class="literal">DEFAULT</code> is used, the default initial schema for all
users is used as the initial schema for the user. The SET SCHEMA command
allows the user to change the schema for the duration of the session. Only
a user with the DBA role can execute this statement.</p>
<a name="N1186D" class="indexterm"></a>
<p>
<a name="set_password-sql"></a><span class="bold"><strong>SET
PASSWORD</strong></span>
</p>
<p>
<span class="emphasis"><em>set password statement (HyperSQL)</em></span>
</p>
<p>
<code class="literal">&lt;set password statement&gt; ::= SET PASSWORD
&lt;password&gt;</code>
</p>
<p>Set the password for the current user.
<code class="literal">&lt;password&gt;</code> is a string enclosed with single quote
characters and is case-sensitive.</p>
<a name="N11882" class="indexterm"></a>
<p>
<span class="bold"><strong>SET INITIAL SCHEMA</strong></span>
</p>
<p>
<span class="emphasis"><em>set the initial schema for the current user
(HyperSQL)</em></span>
</p>
<p>
<code class="literal">&lt;set initial schema statement&gt; ::= SET INITIAL
SCHEMA &lt;schema name&gt; | DEFAULT</code>
</p>
<p>Change the initial schema for the current user. The initial
schema is the schema used by default for SQL statements issued during a
session. If <code class="literal">DEFAULT</code> is used, the default initial schema
for all users is used as the initial schema for the current user. The
separate SET SCHEMA command allows the user to change the schema for the
duration of the session. See also the <a class="link" href="sessions-chapt.html" title="Chapter&nbsp;3.&nbsp;Sessions and Transactions">Sessions and Transactions</a> chapter.</p>
<a name="N1189B" class="indexterm"></a>
<p>
<span class="bold"><strong>SET DATABASE DEFAULT INITIAL
SCHEMA</strong></span>
</p>
<p>
<span class="emphasis"><em>set the default initial schema for all users
(HyperSQL)</em></span>
</p>
<p>
<code class="literal">&lt;set database default initial schema statement&gt;
::= SET DATABASE DEFAULT INITIAL SCHEMA &lt;schema
name&gt;</code>
</p>
<p>Sets the initial schema for new users. This schema can later be
changed with the <code class="literal">&lt;set initial schema statement&gt;</code>
command.</p>
<a name="N118AF" class="indexterm"></a>
<p>
<span class="bold"><strong>CREATE ROLE</strong></span>
</p>
<p>
<span class="emphasis"><em>role definition</em></span>
</p>
<p>
<code class="literal">&lt;role definition&gt; ::= CREATE ROLE &lt;role
name&gt; [ WITH ADMIN &lt;grantor&gt; ]</code>
</p>
<p>Defines a new role. Initially the role has no rights, except
those of the PUBLIC role. Only a user with the DBA role can execute this
command.</p>
<a name="N118C0" class="indexterm"></a>
<p>
<span class="bold"><strong>DROP ROLE</strong></span>
</p>
<p>
<span class="emphasis"><em>drop role statement</em></span>
</p>
<p>
<code class="literal">&lt;drop role statement&gt; ::= DROP ROLE &lt;role
name&gt;</code>
</p>
<p>Drop (destroy) a role. If the specified role is the authorization
for a schema, the schema is destroyed. Only a user with the DBA role can
execute this statement.</p>
<a name="N118D1" class="indexterm"></a>
<p>
<span class="bold"><strong>GRANTED BY</strong></span>
</p>
<p>
<span class="emphasis"><em>grantor determination</em></span>
</p>
<p>
<code class="literal">GRANTED BY &lt;grantor&gt;</code>
</p>
<p>
<code class="literal">&lt;grantor&gt; ::= CURRENT_USER |
CURRENT_ROLE</code>
</p>
<p>The authorization that is granting or revoking a role or
privileges. The optional <code class="literal">GRANTED BY &lt;grantor&gt;</code>
clause can be used in various statements that perform GRANT or REVOKE
actions. If the clause is not used, the authorization is CURRENT_USER.
Otherwise, it is the specified authorization.</p>
<a name="N118E8" class="indexterm"></a>
<p>
<span class="bold"><strong>GRANT</strong></span>
</p>
<p>
<span class="emphasis"><em>grant privilege statement</em></span>
</p>
<p>
<code class="literal">&lt;grant privilege statement&gt; ::= GRANT
&lt;privileges&gt; TO &lt;grantee&gt; [ { &lt;comma&gt; &lt;grantee&gt;
}... ] [ WITH GRANT OPTION ] [ GRANTED BY &lt;grantor&gt;
]</code>
</p>
<p>Assign privileges on schema objects to roles or users. Each
<code class="literal">&lt;grantee&gt;</code> is a role or a user. If <code class="literal">[ WITH
GRANT OPTION ]</code> is specified, then the
<code class="literal">&lt;grantee&gt;</code> can assign the privileges to other
<code class="literal">&lt;grantee&gt;</code> objects.</p>
<p>
<code class="literal">&lt;privileges&gt; ::= &lt;object privileges&gt; ON
&lt;object name&gt;</code>
</p>
<p>
<code class="literal">&lt;object name&gt; ::= [ TABLE ] &lt;table name&gt; |
DOMAIN &lt;domain name&gt; | COLLATION &lt;collation name&gt; | CHARACTER
SET &lt;character set name&gt; | TRANSLATION &lt;transliteration name&gt;
| TYPE &lt;user-defined type name&gt; | SEQUENCE &lt;sequence generator
name&gt; | &lt;specific routine designator&gt; | ROUTINE &lt;routine
name&gt; | FUNCTION &lt;function name&gt; | PROCEDURE &lt;procedure
name&gt;</code>
</p>
<p>
<code class="literal">&lt;object privileges&gt; ::= ALL PRIVILEGES |
&lt;action&gt; [ { &lt;comma&gt; &lt;action&gt; }... ]</code>
</p>
<p>
<code class="literal">&lt;action&gt; ::= SELECT | SELECT &lt;left paren&gt;
&lt;privilege column list&gt; &lt;right paren&gt; | DELETE | INSERT [
&lt;left paren&gt; &lt;privilege column list&gt; &lt;right paren&gt; ] |
UPDATE [ &lt;left paren&gt; &lt;privilege column list&gt; &lt;right
paren&gt; ] | REFERENCES [ &lt;left paren&gt; &lt;privilege column
list&gt; &lt;right paren&gt; ] | USAGE | TRIGGER |
EXECUTE</code>
</p>
<p>
<code class="literal">&lt;privilege column list&gt; ::= &lt;column name
list&gt;</code>
</p>
<p>
<code class="literal">&lt;grantee&gt; ::= PUBLIC | &lt;authorization
identifier&gt;</code>
</p>
<p>The <code class="literal">&lt;object privileges&gt;</code> that can be used
depend on the type of the <code class="literal">&lt;object name&gt;</code>. These
are discussed in the previous section. For a table, if
<code class="literal">&lt;privilege column list&gt;</code> is not specified, then
the privilege is granted on the table, which includes all of its columns
and any column that may be added to it in the future. For routines, the
name of the routine can be specified in two ways, either as the generic
name as the specific name. HyperSQL allows referencing all overloaded
versions of a routine at the same time, using its name. This differs from
the SQL Standard which requires the use of <code class="literal">&lt;specific routine
designator&gt;</code> to grant privileges separately on each different
signature of the routine.</p>
<p>Each <code class="literal">&lt;grantee&gt;</code> is the name of a role or
a user. Examples of GRANT statement are given below:</p>
<div class="informalexample">
<pre class="programlisting">GRANT ALL ON SEQUENCE aSequence TO roleOrUser
GRANT SELELCT ON aTable TO roleOrUser
GRANT SELECT, UPDATE ON aTABLE TO roleOrUser1, roleOrUser2
GRANT SELECT(columnA, columnB), UPDATE(columnA, columnB) ON TABLE aTable TO roleOrUser
GRANT EXECUTE ON SPECIFIC ROUTINE aroutine_1234 TO rolOrUser
</pre>
</div>
<p>As mentioned in the general discussion, it is better to define a
role for the collection of all the privileges required by an application.
This role is then granted to any user. If further changes are made to the
privileges of this role, they are automatically reflected in all the users
that have the role.</p>
<a name="N1192F" class="indexterm"></a>
<p>
<span class="bold"><strong>GRANT</strong></span>
</p>
<p>
<span class="emphasis"><em>grant role statement</em></span>
</p>
<p>
<code class="literal">&lt;grant role statement&gt; ::= GRANT &lt;role name&gt;
[ { &lt;comma&gt; &lt;role name&gt; }... ] TO &lt;grantee&gt; [ {
&lt;comma&gt; &lt;grantee&gt; }... ] [ WITH ADMIN OPTION ] [ GRANTED BY
&lt;grantor&gt; ]</code>
</p>
<p>Assign roles to roles or users. One or more roles can be assigned
to one or more <code class="literal">&lt;grantee&gt;</code> objects. A
<code class="literal">&lt;grantee&gt;</code> is a user or a role. If the <code class="literal">[
WITH ADMIN OPTION ]</code> is specified, then each
<code class="literal">&lt;grantee&gt;</code> can grant the newly assigned roles to
other grantees. An example of user and role creation with grants is given
below:</p>
<div class="informalexample">
<pre class="programlisting">CREATE USER appuser
CREATE ROLE approle
GRANT approle TO appuser
GRANT SELECT, UPDATE ON TABLE atable TO approle
GRANT USAGE ON SEQUENCE asequence to approle
GRANT EXECUTE ON ROUTINE aroutine TO approle
</pre>
</div>
<a name="N1194F" class="indexterm"></a>
<p>
<span class="bold"><strong>REVOKE privilege</strong></span>
</p>
<p>
<span class="emphasis"><em>revoke statement</em></span>
</p>
<p>
<code class="literal">&lt;revoke privilege statement&gt; ::= REVOKE [ GRANT
OPTION FOR ] &lt;privileges&gt; FROM &lt;grantee&gt; [ { &lt;comma&gt;
&lt;grantee&gt; }... ] [ GRANTED BY &lt;grantor&gt; ] RESTRICT |
CASCADE</code>
</p>
<p>Revoke privileges from a user or role.</p>
<a name="N11960" class="indexterm"></a>
<p>
<span class="bold"><strong>REVOKE role</strong></span>
</p>
<p>
<span class="emphasis"><em>revoke role statement</em></span>
</p>
<p>
<code class="literal">&lt;revoke role statement&gt; ::= REVOKE [ ADMIN OPTION
FOR ] &lt;role revoked&gt; [ { &lt;comma&gt; &lt;role revoked&gt; }... ]
FROM &lt;grantee&gt; [ { &lt;comma&gt; &lt;grantee&gt; }... ] [ GRANTED BY
&lt;grantor&gt; ] RESTRICT | CASCADE</code>
</p>
<p>
<code class="literal">&lt;role revoked&gt; ::= &lt;role
name&gt;</code>
</p>
<p>Revoke a role from users or roles.</p>
</div>
</div>
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