catalogs.sgml

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

      <entry><literal><link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.oid</literal></entry>
      <entry><quote>Insert this tuple</quote> function</entry>
     </row>

     <row>
      <entry><structfield>ambeginscan</structfield></entry>
      <entry><type>regproc</type></entry>
      <entry><literal><link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.oid</literal></entry>
      <entry><quote>Start new scan</quote> function</entry>
     </row>

     <row>
      <entry><structfield>amgettuple</structfield></entry>
      <entry><type>regproc</type></entry>
      <entry><literal><link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.oid</literal></entry>
      <entry><quote>Next valid tuple</quote> function</entry>
     </row>

     <row>
      <entry><structfield>amgetmulti</structfield></entry>
      <entry><type>regproc</type></entry>
      <entry><literal><link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.oid</literal></entry>
      <entry><quote>Fetch multiple tuples</quote> function</entry>
     </row>

     <row>
      <entry><structfield>amrescan</structfield></entry>
      <entry><type>regproc</type></entry>
      <entry><literal><link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.oid</literal></entry>
      <entry><quote>Restart this scan</quote> function</entry>
     </row>

     <row>
      <entry><structfield>amendscan</structfield></entry>
      <entry><type>regproc</type></entry>
      <entry><literal><link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.oid</literal></entry>
      <entry><quote>End this scan</quote> function</entry>
     </row>

     <row>
      <entry><structfield>ammarkpos</structfield></entry>
      <entry><type>regproc</type></entry>
      <entry><literal><link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.oid</literal></entry>
      <entry><quote>Mark current scan position</quote> function</entry>
     </row>

     <row>
      <entry><structfield>amrestrpos</structfield></entry>
      <entry><type>regproc</type></entry>
      <entry><literal><link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.oid</literal></entry>
      <entry><quote>Restore marked scan position</quote> function</entry>
     </row>

     <row>
      <entry><structfield>ambuild</structfield></entry>
      <entry><type>regproc</type></entry>
      <entry><literal><link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.oid</literal></entry>
      <entry><quote>Build new index</quote> function</entry>
     </row>

     <row>
      <entry><structfield>ambulkdelete</structfield></entry>
      <entry><type>regproc</type></entry>
      <entry><literal><link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.oid</literal></entry>
      <entry>Bulk-delete function</entry>
     </row>

     <row>
      <entry><structfield>amvacuumcleanup</structfield></entry>
      <entry><type>regproc</type></entry>
      <entry><literal><link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.oid</literal></entry>
      <entry>Post-<command>VACUUM</command> cleanup function</entry>
     </row>

     <row>
      <entry><structfield>amcostestimate</structfield></entry>
      <entry><type>regproc</type></entry>
      <entry><literal><link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.oid</literal></entry>
      <entry>Function to estimate cost of an index scan</entry>
     </row>

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

 </sect1>


 <sect1 id="catalog-pg-amop">
  <title><structname>pg_amop</structname></title>

  <indexterm zone="catalog-pg-amop">
   <primary>pg_amop</primary>
  </indexterm>

  <para>
   The catalog <structname>pg_amop</structname> stores information about operators
   associated with index access method operator classes.  There is one
   row for each operator that is a member of an operator class.
  </para>

  <table>
   <title><structname>pg_amop</> 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>amopclaid</structfield></entry>
      <entry><type>oid</type></entry>
      <entry><literal><link linkend="catalog-pg-opclass"><structname>pg_opclass</structname></link>.oid</literal></entry>
      <entry>The index operator class this entry is for</entry>
     </row>

     <row>
      <entry><structfield>amopsubtype</structfield></entry>
      <entry><type>oid</type></entry>
      <entry><literal><link linkend="catalog-pg-type"><structname>pg_type</structname></link>.oid</literal></entry>
      <entry>Subtype to distinguish multiple entries for one strategy;
             zero for default</entry>
     </row>

     <row>
      <entry><structfield>amopstrategy</structfield></entry>
      <entry><type>int2</type></entry>
      <entry></entry>
      <entry>Operator strategy number</entry>
     </row>

     <row>
      <entry><structfield>amopreqcheck</structfield></entry>
      <entry><type>bool</type></entry>
      <entry></entry>
      <entry>Index hit must be rechecked</entry>
     </row>

     <row>
      <entry><structfield>amopopr</structfield></entry>
      <entry><type>oid</type></entry>
      <entry><literal><link linkend="catalog-pg-operator"><structname>pg_operator</structname></link>.oid</literal></entry>
      <entry>OID of the operator</entry>
     </row>

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

 </sect1>


 <sect1 id="catalog-pg-amproc">
  <title><structname>pg_amproc</structname></title>

  <indexterm zone="catalog-pg-amproc">
   <primary>pg_amproc</primary>
  </indexterm>

  <para>
   The catalog <structname>pg_amproc</structname> stores information about support
   procedures
   associated with index access method operator classes.  There is one
   row for each support procedure belonging to an operator class.
  </para>

  <table>
   <title><structname>pg_amproc</structname> 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>amopclaid</structfield></entry>
      <entry><type>oid</type></entry>
      <entry><literal><link linkend="catalog-pg-opclass"><structname>pg_opclass</structname></link>.oid</literal></entry>
      <entry>The index operator class this entry is for</entry>
     </row>

     <row>
      <entry><structfield>amprocsubtype</structfield></entry>
      <entry><type>oid</type></entry>
      <entry><literal><link linkend="catalog-pg-type"><structname>pg_type</structname></link>.oid</literal></entry>
      <entry>Subtype, if cross-type routine, else zero</entry>
     </row>

     <row>
      <entry><structfield>amprocnum</structfield></entry>
      <entry><type>int2</type></entry>
      <entry></entry>
      <entry>Support procedure number</entry>
     </row>

     <row>
      <entry><structfield>amproc</structfield></entry>
      <entry><type>regproc</type></entry>
      <entry><literal><link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.oid</literal></entry>
      <entry>OID of the procedure</entry>
     </row>

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

 </sect1>


 <sect1 id="catalog-pg-attrdef">
  <title><structname>pg_attrdef</structname></title>

  <indexterm zone="catalog-pg-attrdef">
   <primary>pg_attrdef</primary>
  </indexterm>

  <para>
   The catalog <structname>pg_attrdef</structname> stores column default values.  The main information
   about columns is stored in <structname>pg_attribute</structname>
   (see below).  Only columns that explicitly specify a default value
   (when the table is created or the column is added) will have an
   entry here.
  </para>

  <table>
   <title><structname>pg_attrdef</> 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>adrelid</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 column belongs to</entry>
     </row>

     <row>
      <entry><structfield>adnum</structfield></entry>
      <entry><type>int2</type></entry>
      <entry><literal><link linkend="catalog-pg-attribute"><structname>pg_attribute</structname></link>.attnum</literal></entry>
      <entry>The number of the column</entry>
     </row>

     <row>
      <entry><structfield>adbin</structfield></entry>
      <entry><type>text</type></entry>
      <entry></entry>
      <entry>The internal representation of the column default value</entry>
     </row>

     <row>
      <entry><structfield>adsrc</structfield></entry>
      <entry><type>text</type></entry>
      <entry></entry>
      <entry>A human-readable representation of the default value</entry>
     </row>
    </tbody>
   </tgroup>
  </table>

   <para>
    The <structfield>adsrc</structfield> field is historical, and is best
    not used, because it does not track outside changes that might affect
    the representation of the default value.  Reverse-compiling the
    <structfield>adbin</structfield> field (with <function>pg_get_expr</> for
    example) is a better way to display the default value.
   </para>

 </sect1>


 <sect1 id="catalog-pg-attribute">
  <title><structname>pg_attribute</structname></title>

  <indexterm zone="catalog-pg-attribute">
   <primary>pg_attribute</primary>
  </indexterm>

  <para>
   The catalog <structname>pg_attribute</structname> stores information about
   table columns.  There will be exactly one
   <structname>pg_attribute</structname> row for every column in every
   table in the database.  (There will also be attribute entries for
   indexes, and indeed all objects that have <structname>pg_class</structname>
   entries.)
  </para>

  <para>
   The term attribute is equivalent to column and is used for
   historical reasons.
  </para>

  <table>
   <title><structname>pg_attribute</> 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>attrelid</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 column belongs to</entry>
     </row>

     <row>
      <entry><structfield>attname</structfield></entry>
      <entry><type>name</type></entry>
      <entry></entry>
      <entry>The column name</entry>
     </row>

     <row>
      <entry><structfield>atttypid</structfield></entry>
      <entry><type>oid</type></entry>
      <entry><literal><link linkend="catalog-pg-type"><structname>pg_type</structname></link>.oid</literal></entry>
      <entry>The data type of this column</entry>
     </row>

     <row>
      <entry><structfield>attstattarget</structfield></entry>
      <entry><type>int4</type></entry>
      <entry></entry>
      <entry>
       <structfield>attstattarget</structfield> controls the level of detail
       of statistics accumulated for this column by
       <xref linkend="sql-analyze" endterm="sql-analyze-title">.
       A zero value indicates that no statistics should be collected.
       A negative value says to use the system default statistics target.
       The exact meaning of positive values is data type-dependent.
       For scalar data types, <structfield>attstattarget</structfield>
       is both the target number of <quote>most common values</quote>
       to collect, and the target number of histogram bins to create.
      </entry>
     </row>

     <row>
      <entry><structfield>attlen</structfield></entry>
      <entry><type>int2</type></entry>
      <entry></entry>
      <entry>
       A copy of <literal>pg_type.typlen</literal> of this column's
       type
      </entry>
     </row>

     <row>
      <entry><structfield>attnum</structfield></entry>
      <entry><type>int2</type></entry>
      <entry></entry>
      <entry>
       The number of the column.  Ordinary columns are numbered from 1
       up.  System columns, such as <structfield>oid</structfield>,
       have (arbitrary) negative numbers.
      </entry>
     </row>

     <row>
      <entry><structfield>attndims</structfield></entry>
      <entry><type>int4</type></entry>
      <entry></entry>
      <entry>
       Number of dimensions, if the column is an array type; otherwise 0.
       (Presently, the number of dimensions of an array is not enforced,
       so any nonzero value effectively means <quote>it's an array</>.)
      </entry>
     </row>

     <row>
      <entry><structfield>attcacheoff</structfield></entry>
      <entry><type>int4</type></entry>