grant.sgml

关系型数据库 Postgresql 6.5.2

<refentry id="SQL-GRANT">
 <refmeta>
  <refentrytitle>
   GRANT
  </refentrytitle>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>
 <refnamediv>
  <refname>
   GRANT
  </refname>
  <refpurpose>
   Grants access privilege to a user, a group or all users
  </refpurpose>
 </refnamediv>
 <refsynopsisdiv>
  <refsynopsisdivinfo>
   <date>1998-09-23</date>
  </refsynopsisdivinfo>
  <synopsis>
GRANT <replaceable class="PARAMETER">privilege</replaceable> [, ...] ON <replaceable class="PARAMETER">object</replaceable> [, ...]
    TO { PUBLIC | GROUP <replaceable class="PARAMETER">group</replaceable> | <replaceable class="PARAMETER">username</replaceable> }
  </synopsis>
    
  <refsect2 id="R2-SQL-GRANT-1">
   <refsect2info>
    <date>1998-09-23</date>
   </refsect2info>
   <title>
    Inputs
   </title>
   <para>

    <variablelist>
     <varlistentry>
      <term><replaceable class="PARAMETER">privilege</replaceable></term>
      <listitem>
       <para>
	The possible privileges are:

	<variablelist>
	 <varlistentry>
	  <term>SELECT</term>
	  <listitem>
	   <para>
	    Access all of the columns of a specific
	    table/view.
	   </para>
	  </listitem>
	 </varlistentry>

	 <varlistentry>
	  <term>INSERT</term>
	  <listitem>
	   <para>
	    Insert data into all columns of a
	    specific table.
	   </para>
	  </listitem>
	 </varlistentry>

	 <varlistentry>
	  <term>UPDATE</term>
	  <listitem>
	   <para>
	    Update all columns of a specific
	    table.
	   </para>
	  </listitem>
	 </varlistentry>

	 <varlistentry>
	  <term>DELETE</term>
	  <listitem>
	   <para>
	    Delete rows from a specific table.
	   </para>
	  </listitem>
	 </varlistentry>

	 <varlistentry>
	  <term>RULE</term>
	  <listitem>
	   <para>
	    Define rules on the table/view
	    (See CREATE RULE statement).
	   </para>
	  </listitem>
	 </varlistentry>

	 <varlistentry>
	  <term>ALL</term>
	  <listitem>
	   <para>
	    Grant all privileges.
	   </para>
	  </listitem>
	 </varlistentry>
	</variablelist>
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><replaceable class="PARAMETER">object</replaceable></term>
      <listitem>
       <para>
	The name of an object to which to grant access.
	The possible objects are:

	<itemizedlist spacing="compact" mark="bullet">
	 <listitem>
	  <para>
	   table 
	  </para>
	 </listitem>

	 <listitem>
	  <para>
	   view 
	  </para>
	 </listitem>

	 <listitem>
	  <para>
	   sequence
	  </para>
	 </listitem>

	 <listitem>
	  <para>
	   index
	  </para>
	 </listitem>
	</itemizedlist>
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>PUBLIC</term>
      <listitem>
       <para>
	A short form representing all users.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>GROUP <replaceable class="PARAMETER">group</replaceable></term>
      <listitem>
       <para>
	A <replaceable class="PARAMETER">group</replaceable> to whom to grant privileges.
	In the current release, the group must be created explicitly as described below.
       </para>
      </listitem>
     </varlistentry>	

     <varlistentry>
      <term>
       <replaceable class="PARAMETER">username</replaceable>
      </term>
      <listitem>
       <para>
	The name of a user to whom grant privileges. PUBLIC is a short form
	representing all users.
       </para>
      </listitem>
     </varlistentry>	
    </variablelist>
   </para>
  </refsect2>

  <refsect2 id="R2-SQL-GRANT-2">
   <refsect2info>
    <date>1998-09-23</date>
   </refsect2info>
   <title>
    Outputs
   </title>
   <para>

    <variablelist>
     <varlistentry>
      <term><computeroutput>
CHANGE
       </computeroutput></term>
      <listitem>
       <para>
	Message returned if successful.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><computeroutput>
ERROR:  ChangeAcl: class "<replaceable class="PARAMETER">object</replaceable>" not found
       </computeroutput></term>
      <listitem>
       <para>
	Message returned if the specified object is not available or 
	if it is impossible
	to give privileges to the specified group or users.
       </para>
      </listitem>
     </varlistentry>	
    </variablelist>
   </para>
  </refsect2>
 </refsynopsisdiv>

 <refsect1 id="R1-SQL-GRANT-1">
  <refsect1info>
   <date>1998-09-23</date>
  </refsect1info>
  <title>
   Description
  </title>
  <para>
   <command>GRANT</command> allows the creator of an object to give specific permissions to
   all users (PUBLIC) or to a certain user or group. 
   Users other than the creator don't have any access permission 
   unless the creator GRANTs permissions, after the object
   is created.
  </para>

  <para>
   Once a user has a privilege on an object, he is enabled to exercise
   that privilege.
   There is no need to GRANT privileges to the creator of 
   an object, the creator automatically holds ALL privileges, and can 
   also drop the object. 
  </para>

  <refsect2 id="R2-SQL-GRANT-3">
   <refsect2info>
    <date>1998-09-23</date>
   </refsect2info>
   <title>
    Notes
   </title>

   <para>
    Currently, to grant privileges in <productname>Postgres</productname>
    to only few columns, you must
    create a view having desired columns and then grant privileges
    to that view.
   </para>

   <para>
    Use <command>psql \z</command>
    for further information about permissions 
    on existing objects:
    <programlisting>
	  Database    = lusitania
   +------------------+---------------------------------------------+
   |  Relation        |        Grant/Revoke Permissions             |
   +------------------+---------------------------------------------+
   | mytable          | {"=rw","miriam=arwR","group todos=rw"}      |
   +------------------+---------------------------------------------+
   Legend:
         uname=arwR -- privileges granted to a user
   group gname=arwR -- privileges granted to a GROUP
              =arwR -- privileges granted to PUBLIC

                  r -- SELECT
                  w -- UPDATE/DELETE
                  a -- INSERT
                  R -- RULE
               arwR -- ALL
    </programlisting>

    <tip>
     <para>
      Currently, to create a GROUP you have to insert 
      data manually into table pg_group as:
      <programlisting>
INSERT INTO pg_group VALUES ('todos');
CREATE USER miriam IN GROUP todos;
      </programlisting>
     </para>
    </tip>
   </para>

   <para>
    Refer to REVOKE statements to revoke access privileges.
   </para>
  </refsect2>
 </refsect1>

 <refsect1 id="R1-SQL-GRANT-2">
  <title>
   Usage
  </title>
  <para>
   Grant insert privilege to all users on table films:

   <programlisting>
GRANT INSERT ON films TO PUBLIC;
   </programlisting>
  </para>

  <para>
   Grant all privileges to user manuel on view kinds:

   <programlisting>
GRANT ALL ON kinds TO manuel;
   </programlisting>
  </para>
 </refsect1>

 <refsect1 id="R1-SQL-GRANT-3">
  <title>
   Compatibility
  </title>
  <para>
  </para>
    
  <refsect2 id="R2-SQL-GRANT-4">
   <refsect2info>
    <date>1998-09-23</date>
   </refsect2info>
   <title>
    SQL92
   </title>
   <para>
    The <acronym>SQL92</acronym> syntax for GRANT allows setting privileges 
    for individual columns
    within a table, and allows setting a privilege to grant
    the same privileges to others:

    <synopsis>
GRANT <replaceable class="PARAMETER">privilege</replaceable> [, ...]
    ON <replaceable class="PARAMETER">object</replaceable> [ ( <replaceable class="PARAMETER">column</replaceable> [, ...] ) ] [, ...]
    TO { PUBLIC | <replaceable class="PARAMETER">username</replaceable> [, ...] } [ WITH GRANT OPTION ]
    </synopsis>
   </para>

   <para>
    Fields are compatible with the those in the <acronym>Postgres</acronym>
    implementation, with the following additions:

    <variablelist>
     <varlistentry>
      <term><replaceable class="PARAMETER">privilege</replaceable></term>
      <listitem>
       <para>
	<acronym>SQL92</acronym> permits additional privileges to be specified:

	<variablelist>
	 <varlistentry>
	  <term>SELECT</term>
	  <listitem>
	   <para>
	   </para>
	  </listitem>
	 </varlistentry>

	 <varlistentry>
	  <term>REFERENCES</term>
	  <listitem>
	   <para>
	    Allowed to reference some or all of the columns of a specific
	    table/view in integrity constraints.
	   </para>
	  </listitem>
	 </varlistentry>	

	 <varlistentry>
	  <term>USAGE</term>
	  <listitem>
	   <para>
	    Allowed to use a domain, character set, collation
	    or translation.
	    If an object specifies anything other than a table/view,
	    <replaceable class="PARAMETER">privilege</replaceable>
	    must specify only USAGE.
	   </para>
	  </listitem>
	 </varlistentry>	
	</variablelist>
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><replaceable class="PARAMETER">object</replaceable></term>
      <listitem>
       <para>

	<variablelist>
	 <varlistentry>
	  <term>[ TABLE ] <replaceable class="PARAMETER">table</replaceable></term>
	  <listitem>
	   <para>
	    <acronym>SQL92</acronym> allows the additional
	    non-functional keyword <literal>TABLE</literal>.
	   </para>
	  </listitem>
	 </varlistentry>

	 <varlistentry>
	  <term>CHARACTER SET</term>
	  <listitem>
	   <para>
	    Allowed to use the specified character set.
	   </para>
	  </listitem>
	 </varlistentry>	

	 <varlistentry>
	  <term>COLLATION</term>
	  <listitem>
	   <para>
	    Allowed to use the specified collation sequence.
	   </para>
	  </listitem>
	 </varlistentry>	

	 <varlistentry>
	  <term>TRANSLATION</term>
	  <listitem>
	   <para>
	    Allowed to use the specified character set translation.
	   </para>
	  </listitem>
	 </varlistentry>	

	 <varlistentry>
	  <term>DOMAIN</term>
	  <listitem>
	   <para>
	    Allowed to use the specified domain.
	   </para>
	  </listitem>
	 </varlistentry>	

	 <varlistentry>
	  <term>WITH GRANT OPTION</term>
	  <listitem>
	   <para>
	    Allowed to grant the same privilege to others.
	   </para>
	  </listitem>
	 </varlistentry>	
	</variablelist>
       </para>
      </listitem>
     </varlistentry>
    </variablelist>
   </para>
  </refsect2>
 </refsect1>
</refentry>

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