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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 Vsnapshot" /><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 11.5 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>
