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- <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>dblink_fetch</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets V1.79.1" /><link rel="prev" href="contrib-dblink-open.html" title="dblink_open" /><link rel="next" href="contrib-dblink-close.html" title="dblink_close" /></head><body><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">dblink_fetch</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="contrib-dblink-open.html" title="dblink_open">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="dblink.html" title="F.10. dblink">Up</a></td><th width="60%" align="center">F.10. dblink</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 12.4 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="contrib-dblink-close.html" title="dblink_close">Next</a></td></tr></table><hr></hr></div><div class="refentry" id="CONTRIB-DBLINK-FETCH"><div class="titlepage"></div><a id="id-1.11.7.19.11.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle">dblink_fetch</span></h2><p>dblink_fetch — returns rows from an open cursor in a remote database</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="synopsis">
- dblink_fetch(text cursorname, int howmany [, bool fail_on_error]) returns setof record
- dblink_fetch(text connname, text cursorname, int howmany [, bool fail_on_error]) returns setof record
- </pre></div><div class="refsect1" id="id-1.11.7.19.11.5"><h2>Description</h2><p>
- <code class="function">dblink_fetch</code> fetches rows from a cursor previously
- established by <code class="function">dblink_open</code>.
- </p></div><div class="refsect1" id="id-1.11.7.19.11.6"><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>connname</code></em></span></dt><dd><p>
- Name of the connection to use; omit this parameter to use the
- unnamed connection.
- </p></dd><dt><span class="term"><em class="parameter"><code>cursorname</code></em></span></dt><dd><p>
- The name of the cursor to fetch from.
- </p></dd><dt><span class="term"><em class="parameter"><code>howmany</code></em></span></dt><dd><p>
- The maximum number of rows to retrieve. The next <em class="parameter"><code>howmany</code></em>
- rows are fetched, starting at the current cursor position, moving
- forward. Once the cursor has reached its end, no more rows are produced.
- </p></dd><dt><span class="term"><em class="parameter"><code>fail_on_error</code></em></span></dt><dd><p>
- If true (the default when omitted) then an error thrown on the
- remote side of the connection causes an error to also be thrown
- locally. If false, the remote error is locally reported as a NOTICE,
- and the function returns no rows.
- </p></dd></dl></div></div><div class="refsect1" id="id-1.11.7.19.11.7"><h2>Return Value</h2><p>
- The function returns the row(s) fetched from the cursor. To use this
- function, you will need to specify the expected set of columns,
- as previously discussed for <code class="function">dblink</code>.
- </p></div><div class="refsect1" id="id-1.11.7.19.11.8"><h2>Notes</h2><p>
- On a mismatch between the number of return columns specified in the
- <code class="literal">FROM</code> clause, and the actual number of columns returned by the
- remote cursor, an error will be thrown. In this event, the remote cursor
- is still advanced by as many rows as it would have been if the error had
- not occurred. The same is true for any other error occurring in the local
- query after the remote <code class="command">FETCH</code> has been done.
- </p></div><div class="refsect1" id="id-1.11.7.19.11.9"><h2>Examples</h2><pre class="screen">
- SELECT dblink_connect('dbname=postgres options=-csearch_path=');
- dblink_connect
- ----------------
- OK
- (1 row)
-
- SELECT dblink_open('foo', 'select proname, prosrc from pg_proc where proname like ''bytea%''');
- dblink_open
- -------------
- OK
- (1 row)
-
- SELECT * FROM dblink_fetch('foo', 5) AS (funcname name, source text);
- funcname | source
- ----------+----------
- byteacat | byteacat
- byteacmp | byteacmp
- byteaeq | byteaeq
- byteage | byteage
- byteagt | byteagt
- (5 rows)
-
- SELECT * FROM dblink_fetch('foo', 5) AS (funcname name, source text);
- funcname | source
- -----------+-----------
- byteain | byteain
- byteale | byteale
- bytealike | bytealike
- bytealt | bytealt
- byteane | byteane
- (5 rows)
-
- SELECT * FROM dblink_fetch('foo', 5) AS (funcname name, source text);
- funcname | source
- ------------+------------
- byteanlike | byteanlike
- byteaout | byteaout
- (2 rows)
-
- SELECT * FROM dblink_fetch('foo', 5) AS (funcname name, source text);
- funcname | source
- ----------+--------
- (0 rows)
- </pre></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="contrib-dblink-open.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="dblink.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="contrib-dblink-close.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">dblink_open </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> dblink_close</td></tr></table></div></body></html>
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