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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>52.23. pg_foreign_data_wrapper</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="catalog-pg-extension.html" title="52.22. pg_extension" /><link rel="next" href="catalog-pg-foreign-server.html" title="52.24. pg_foreign_server" /></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">52.23. <code xmlns="http://www.w3.org/1999/xhtml" class="structname">pg_foreign_data_wrapper</code></th></tr><tr><td width="10%" align="left"><a accesskey="p" href="catalog-pg-extension.html" title="52.22. pg_extension">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="catalogs.html" title="Chapter 52. System Catalogs">Up</a></td><th width="60%" align="center">Chapter 52. System Catalogs</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="catalog-pg-foreign-server.html" title="52.24. pg_foreign_server">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="CATALOG-PG-FOREIGN-DATA-WRAPPER"><div class="titlepage"><div><div><h2 class="title" style="clear: both">52.23. <code class="structname">pg_foreign_data_wrapper</code></h2></div></div></div><a id="id-1.10.4.25.2" class="indexterm"></a><p>
The catalog <code class="structname">pg_foreign_data_wrapper</code> stores
foreign-data wrapper definitions. A foreign-data wrapper is the
mechanism by which external data, residing on foreign servers, is
accessed.
</p><div class="table" id="id-1.10.4.25.4"><p class="title"><strong>Table 52.23. <code class="structname">pg_foreign_data_wrapper</code> Columns</strong></p><div class="table-contents"><table class="table" summary="pg_foreign_data_wrapper Columns" border="1"><colgroup><col /><col /><col /><col /></colgroup><thead><tr><th>Name</th><th>Type</th><th>References</th><th>Description</th></tr></thead><tbody><tr><td><code class="structfield">oid</code></td><td><code class="type">oid</code></td><td> </td><td>Row identifier (hidden attribute; must be explicitly selected)</td></tr><tr><td><code class="structfield">fdwname</code></td><td><code class="type">name</code></td><td> </td><td>Name of the foreign-data wrapper</td></tr><tr><td><code class="structfield">fdwowner</code></td><td><code class="type">oid</code></td><td><code class="literal"><a class="link" href="catalog-pg-authid.html" title="52.8. pg_authid"><code class="structname">pg_authid</code></a>.oid</code></td><td>Owner of the foreign-data wrapper</td></tr><tr><td><code class="structfield">fdwhandler</code></td><td><code class="type">oid</code></td><td><code class="literal"><a class="link" href="catalog-pg-proc.html" title="52.39. pg_proc"><code class="structname">pg_proc</code></a>.oid</code></td><td>
References a handler function that is responsible for
supplying execution routines for the foreign-data wrapper.
Zero if no handler is provided
</td></tr><tr><td><code class="structfield">fdwvalidator</code></td><td><code class="type">oid</code></td><td><code class="literal"><a class="link" href="catalog-pg-proc.html" title="52.39. pg_proc"><code class="structname">pg_proc</code></a>.oid</code></td><td>
References a validator function that is responsible for
checking the validity of the options given to the
foreign-data wrapper, as well as options for foreign servers and user
mappings using the foreign-data wrapper. Zero if no validator
is provided
</td></tr><tr><td><code class="structfield">fdwacl</code></td><td><code class="type">aclitem[]</code></td><td> </td><td>
Access privileges; see
<a class="xref" href="sql-grant.html" title="GRANT"><span class="refentrytitle">GRANT</span></a> and
<a class="xref" href="sql-revoke.html" title="REVOKE"><span class="refentrytitle">REVOKE</span></a>
for details
</td></tr><tr><td><code class="structfield">fdwoptions</code></td><td><code class="type">text[]</code></td><td> </td><td>
Foreign-data wrapper specific options, as <span class="quote">“<span class="quote">keyword=value</span>”</span> strings
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