move.sgml

关系型数据库 Postgresql 6.5.2

<refentry id="SQL-MOVE">
 <refmeta>
  <refentrytitle>
   MOVE
  </refentrytitle>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>
 <refnamediv>
  <refname>
   MOVE
  </refname>
  <refpurpose>
   Moves cursor position
  </refpurpose>
 </refnamediv>                
 <refsynopsisdiv>
  <refsynopsisdivinfo>
   <date>1998-09-24</date>
  </refsynopsisdivinfo>
  <synopsis>
MOVE [ <replaceable class="PARAMETER">selector</replaceable> ] [ <replaceable class="PARAMETER">count</replaceable> ] 
    { IN | FROM } <replaceable class="PARAMETER">cursor</replaceable>
    FETCH [ RELATIVE ] [ { [ <replaceable class="PARAMETER">#</replaceable> | ALL | NEXT | PRIOR ] } ] FROM ] <replaceable class="PARAMETER">cursor</replaceable>
  </synopsis>
 </refsynopsisdiv>

 <refsect1 id="R1-SQL-MOVE-1">
  <refsect1info>
   <date>1998-09-24</date>
  </refsect1info>
  <title>
   Description
  </title>
  <para>
   <command>MOVE</command> allows a user to move cursor position a specified
   number of rows.
   <command>MOVE</command> works like the <command>FETCH</command> command,
   but only positions the cursor and does
   not return rows.
  </para>
  <para>
   Refer to the <command>FETCH</command> command for details on syntax and usage.
  </para>

  <refsect2 id="R2-SQL-MOVE-3">
   <refsect2info>
    <date>1998-09-24</date>
   </refsect2info>
   <title>
    Notes
   </title>
   <para>
    <command>MOVE</command> is a <productname>Postgres</productname>
    language extension.
   </para>
   <para>
    Refer to <command>FETCH</command> for a description
    of valid arguments.
    Refer to <command>DECLARE</command> to declare a cursor.
    Refer to <command>BEGIN WORK</command>, <command>COMMIT WORK</command>,
    <command>ROLLBACK WORK</command> statements
    for further information about transactions.
   </para>
  </refsect2>
 </refsect1>

 <refsect1 id="R1-SQL-MOVE-2">
  <title>
   Usage
  </title>
  <para>
   Set up and use a cursor:

   <programlisting>
BEGIN WORK;
DECLARE liahona CURSOR  FOR SELECT * FROM films;
--Skip first 5 rows:
MOVE FORWARD 5 IN liahona;
<computeroutput>
MOVE
</computeroutput>
--Fetch 6th row in the cursor liahona:
FETCH 1 IN liahona;
<computeroutput>
FETCH

  code |title |did| date_prod|kind      |len
  -----+------+---+----------+----------+------
  P_303|48 Hrs|103|1982-10-22|Action    | 01:37
  (1 row)
</computeroutput>
-- close the cursor liahona and commit work:
CLOSE liahona;
COMMIT WORK;
   </programlisting>
  </para>
 </refsect1>

 <refsect1 id="R1-SQL-MOVE-3">
  <title>
   Compatibility
  </title>
  <para>
  </para>
	
  <refsect2 id="R2-SQL-MOVE-4">
   <refsect2info>
    <date>1998-09-01</date>
   </refsect2info>
   <title>
    SQL92
   </title>
   <para>
    There is no SQL92 <command>MOVE</command> statement. 
    Instead, <acronym>SQL92</acronym> allows
    one to <command>FETCH</command> rows from an absolute cursor position,
    implicitly moving the cursor to the correct place.
   </para>
  </refsect2>
 </refsect1>
</refentry>

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