<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!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_get_pkey</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-cancel-query.html" title="dblink_cancel_query" /><link rel="next" href="contrib-dblink-build-sql-insert.html" title="dblink_build_sql_insert" /></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_get_pkey</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="contrib-dblink-cancel-query.html" title="dblink_cancel_query">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-build-sql-insert.html" title="dblink_build_sql_insert">Next</a></td></tr></table><hr></hr></div><div class="refentry" id="CONTRIB-DBLINK-GET-PKEY"><div class="titlepage"></div><a id="id-1.11.7.19.20.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle">dblink_get_pkey</span></h2><p>dblink_get_pkey — returns the positions and field names of a relation's
primary key fields
</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="synopsis">
dblink_get_pkey(text relname) returns setof dblink_pkey_results
</pre></div><div class="refsect1" id="id-1.11.7.19.20.5"><h2>Description</h2><p>
<code class="function">dblink_get_pkey</code> provides information about the primary
key of a relation in the local database. This is sometimes useful
in generating queries to be sent to remote databases.
</p></div><div class="refsect1" id="id-1.11.7.19.20.6"><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>relname</code></em></span></dt><dd><p>
Name of a local relation, for example <code class="literal">foo</code> or
<code class="literal">myschema.mytab</code>. Include double quotes if the
name is mixed-case or contains special characters, for
example <code class="literal">"FooBar"</code>; without quotes, the string
will be folded to lower case.
</p></dd></dl></div></div><div class="refsect1" id="id-1.11.7.19.20.7"><h2>Return Value</h2><p>
Returns one row for each primary key field, or no rows if the relation
has no primary key. The result row type is defined as
</p><pre class="programlisting">
CREATE TYPE dblink_pkey_results AS (position int, colname text);
</pre><p>
The <code class="literal">position</code> column simply runs from 1 to <em class="replaceable"><code>N</code></em>;
it is the number of the field within the primary key, not the number
within the table's columns.
</p></div><div class="refsect1" id="id-1.11.7.19.20.8"><h2>Examples</h2><pre class="screen">
CREATE TABLE foobar (
f1 int,
f2 int,
f3 int,
PRIMARY KEY (f1, f2, f3)
);
CREATE TABLE
SELECT * FROM dblink_get_pkey('foobar');
position | colname
----------+---------
1 | f1
2 | f2
3 | f3
(3 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-cancel-query.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-build-sql-insert.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">dblink_cancel_query </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> dblink_build_sql_insert</td></tr></table></div></body></html>
