catalogs.sgml

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

      <entry><type>bool</type></entry>
      <entry></entry>
      <entry>True if table has rules; see
       <structname>pg_rewrite</structname> catalog.
      </entry>
     </row>

     <row>
      <entry><structfield>relhassubclass</structfield></entry>
      <entry><type>bool</type></entry>
      <entry></entry>
      <entry>True if table has (or once had) any inheritance children.</entry>
     </row>

     <row>
      <entry><structfield>relacl</structfield></entry>
      <entry><type>aclitem[]</type></entry>
      <entry></entry>
      <entry>
       Access privileges; see
       <xref linkend="sql-grant" endterm="sql-grant-title"> and
       <xref linkend="sql-revoke" endterm="sql-revoke-title">
       for details.
      </entry>
     </row>
    </tbody>
   </tgroup>
  </table>
 </sect1>

 <sect1 id="catalog-pg-constraint">
  <title><structname>pg_constraint</structname></title>

  <indexterm zone="catalog-pg-constraint">
   <primary>pg_constraint</primary>
  </indexterm>

  <para>
   The catalog <structname>pg_constraint</structname> stores check, primary key, unique, and foreign
   key constraints on tables.  (Column constraints are not treated
   specially.  Every column constraint is equivalent to some table
   constraint.)  Not-null constraints are represented in the
   <structname>pg_attribute</> catalog.
  </para>

  <para>
   Check constraints on domains are stored here, too.
  </para>

  <table>
   <title><structname>pg_constraint</> Columns</title>

   <tgroup cols=4>
    <thead>
     <row>
      <entry>Name</entry>
      <entry>Type</entry>
      <entry>References</entry>
      <entry>Description</entry>
     </row>
    </thead>

    <tbody>
     <row>
      <entry><structfield>conname</structfield></entry>
      <entry><type>name</type></entry>
      <entry></entry>
      <entry>Constraint name (not necessarily unique!)</entry>
     </row>

     <row>
      <entry><structfield>connamespace</structfield></entry>
      <entry><type>oid</type></entry>
      <entry><literal><link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.oid</literal></entry>
      <entry>
       The OID of the namespace that contains this constraint
      </entry>
     </row>

     <row>
      <entry><structfield>contype</structfield></entry>
      <entry><type>char</type></entry>
      <entry></entry>
      <entry>
        <literal>c</> = check constraint,
        <literal>f</> = foreign key constraint,
        <literal>p</> = primary key constraint,
        <literal>u</> = unique constraint
      </entry>
     </row>

     <row>
      <entry><structfield>condeferrable</structfield></entry>
      <entry><type>bool</type></entry>
      <entry></entry>
      <entry>Is the constraint deferrable?</entry>
     </row>

     <row>
      <entry><structfield>condeferred</structfield></entry>
      <entry><type>bool</type></entry>
      <entry></entry>
      <entry>Is the constraint deferred by default?</entry>
     </row>

     <row>
      <entry><structfield>conrelid</structfield></entry>
      <entry><type>oid</type></entry>
      <entry><literal><link linkend="catalog-pg-class"><structname>pg_class</structname></link>.oid</literal></entry>
      <entry>The table this constraint is on; 0 if not a table constraint</entry>
     </row>

     <row>
      <entry><structfield>contypid</structfield></entry>
      <entry><type>oid</type></entry>
      <entry><literal><link linkend="catalog-pg-type"><structname>pg_type</structname></link>.oid</literal></entry>
      <entry>The domain this constraint is on; 0 if not a domain constraint</entry>
     </row>

     <row>
      <entry><structfield>confrelid</structfield></entry>
      <entry><type>oid</type></entry>
      <entry><literal><link linkend="catalog-pg-class"><structname>pg_class</structname></link>.oid</literal></entry>
      <entry>If a foreign key, the referenced table; else 0</entry>
     </row>

     <row>
      <entry><structfield>confupdtype</structfield></entry>
      <entry><type>char</type></entry>
      <entry></entry>
      <entry>Foreign key update action code</entry>
     </row>

     <row>
      <entry><structfield>confdeltype</structfield></entry>
      <entry><type>char</type></entry>
      <entry></entry>
      <entry>Foreign key deletion action code</entry>
     </row>

     <row>
      <entry><structfield>confmatchtype</structfield></entry>
      <entry><type>char</type></entry>
      <entry></entry>
      <entry>Foreign key match type</entry>
     </row>

     <row>
      <entry><structfield>conkey</structfield></entry>
      <entry><type>int2[]</type></entry>
      <entry><literal><link linkend="catalog-pg-attribute"><structname>pg_attribute</structname></link>.attnum</></entry>
      <entry>If a table constraint, list of columns which the constraint constrains</entry>
     </row>

     <row>
      <entry><structfield>confkey</structfield></entry>
      <entry><type>int2[]</type></entry>
      <entry><literal><link linkend="catalog-pg-attribute"><structname>pg_attribute</structname></link>.attnum</></entry>
      <entry>If a foreign key, list of the referenced columns</entry>
     </row>

     <row>
      <entry><structfield>conbin</structfield></entry>
      <entry><type>text</type></entry>
      <entry></entry>
      <entry>If a check constraint, an internal representation of the expression</entry>
     </row>

     <row>
      <entry><structfield>consrc</structfield></entry>
      <entry><type>text</type></entry>
      <entry></entry>
      <entry>If a check constraint, a human-readable representation of the expression</entry>
     </row>
    </tbody>
   </tgroup>
  </table>

  <note>
   <para>
    <structfield>consrc</structfield> is not updated when referenced objects
    change; for example, it won't track renaming of columns.  Rather than
    relying on this field, it's best to use <function>pg_get_constraintdef()</>
    to extract the definition of a check constraint.
   </para>
  </note>

  <note>
   <para>
    <literal>pg_class.relchecks</literal> needs to agree with the
    number of check-constraint entries found in this table for the
    given relation.
   </para>
  </note>

 </sect1>

 <sect1 id="catalog-pg-conversion">
  <title><structname>pg_conversion</structname></title>

  <indexterm zone="catalog-pg-conversion">
   <primary>pg_conversion</primary>
  </indexterm>

  <para>
   The catalog <structname>pg_conversion</structname> describes the
   available encoding conversion procedures.  See
   <xref linkend="sql-createconversion" endterm="sql-createconversion-title">
   for more information.
  </para>

  <table>
   <title><structname>pg_conversion</> Columns</title>

   <tgroup cols=4>
    <thead>
     <row>
      <entry>Name</entry>
      <entry>Type</entry>
      <entry>References</entry>
      <entry>Description</entry>
     </row>
    </thead>

    <tbody>
     <row>
      <entry><structfield>conname</structfield></entry>
      <entry><type>name</type></entry>
      <entry></entry>
      <entry>Conversion name (unique within a namespace)</entry>
     </row>

     <row>
      <entry><structfield>connamespace</structfield></entry>
      <entry><type>oid</type></entry>
      <entry><literal><link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.oid</literal></entry>
      <entry>
       The OID of the namespace that contains this conversion
      </entry>
     </row>

     <row>
      <entry><structfield>conowner</structfield></entry>
      <entry><type>oid</type></entry>
      <entry><literal><link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.oid</literal></entry>
      <entry>Owner of the conversion</entry>
     </row>

     <row>
      <entry><structfield>conforencoding</structfield></entry>
      <entry><type>int4</type></entry>
      <entry></entry>
      <entry>Source encoding ID</entry>
     </row>

     <row>
      <entry><structfield>contoencoding</structfield></entry>
      <entry><type>int4</type></entry>
      <entry></entry>
      <entry>Destination encoding ID</entry>
     </row>

     <row>
      <entry><structfield>conproc</structfield></entry>
      <entry><type>regproc</type></entry>
      <entry><literal><link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.oid</literal></entry>
      <entry>Conversion procedure</entry>
     </row>

     <row>
      <entry><structfield>condefault</structfield></entry>
      <entry><type>bool</type></entry>
      <entry></entry>
      <entry>True if this is the default conversion</entry>
     </row>

    </tbody>
   </tgroup>
  </table>

 </sect1>

 <sect1 id="catalog-pg-database">
  <title><structname>pg_database</structname></title>

  <indexterm zone="catalog-pg-database">
   <primary>pg_database</primary>
  </indexterm>

  <para>
   The catalog <structname>pg_database</structname> stores information
   about the available databases.  Databases are created with the
   <command>CREATE DATABASE</command> command.  Consult
   <xref linkend="managing-databases"> for details about the meaning of some of the
   parameters.
  </para>

  <para>
   Unlike most system catalogs, <structname>pg_database</structname>
   is shared across all databases of a cluster: there is only one
   copy of <structname>pg_database</structname> per cluster, not
   one per database.
  </para>

  <table>
   <title><structname>pg_database</> Columns</title>

   <tgroup cols=4>
    <thead>
     <row>
      <entry>Name</entry>
      <entry>Type</entry>
      <entry>References</entry>
      <entry>Description</entry>
     </row>
    </thead>

    <tbody>
     <row>
      <entry><structfield>datname</structfield></entry>
      <entry><type>name</type></entry>
      <entry></entry>
      <entry>Database name</entry>
     </row>

     <row>
      <entry><structfield>datdba</structfield></entry>
      <entry><type>oid</type></entry>
      <entry><literal><link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.oid</literal></entry>
      <entry>Owner of the database, usually the user who created it</entry>
     </row>

     <row>
      <entry><structfield>encoding</structfield></entry>
      <entry><type>int4</type></entry>
      <entry></entry>
      <entry>Character encoding for this database</entry>
     </row>

     <row>
      <entry><structfield>datistemplate</structfield></entry>
      <entry><type>bool</type></entry>
      <entry></entry>
      <entry>
       If true then this database can be used in the
       <literal>TEMPLATE</literal> clause of <command>CREATE
       DATABASE</command> to create a new database as a clone of
       this one.
      </entry>
     </row>

     <row>
      <entry><structfield>datallowconn</structfield></entry>
      <entry><type>bool</type></entry>
      <entry></entry>
      <entry>
       If false then no one can connect to this database.  This is
       used to protect the <literal>template0</> database from being altered.
      </entry>
     </row>

     <row>
      <entry><structfield>datconnlimit</structfield></entry>
      <entry><type>int4</type></entry>
      <entry></entry>
      <entry>
       Sets maximum number of concurrent connections that can be made 
       to this database.  -1 means no limit.
      </entry>
     </row>

     <row>
      <entry><structfield>datlastsysoid</structfield></entry>
      <entry><type>oid</type></entry>
      <entry></entry>
      <entry>
       Last system OID in the database; useful
       particularly to <application>pg_dump</application>
      </entry>
     </row>

     <row>
      <entry><structfield>datvacuumxid</structfield></entry>
      <entry><type>xid</type></entry>
      <entry></entry>
      <entry>
       All rows inserted or deleted by transaction IDs before this one
       have been marked as known committed or known aborted in this database.
       This is used to determine when commit-log space can be recycled.
      </entry>
     </row>

     <row>
      <entry><structfield>datfrozenxid</structfield></entry>
      <entry><type>xid</type></entry>
      <entry></entry>
      <entry>
       All rows inserted by transaction IDs before this one have been
       relabeled with a permanent (<quote>frozen</>) transaction ID in this
       database.