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diff --git a/doc/src/sgml/html/contrib-dblink-connect.html b/doc/src/sgml/html/contrib-dblink-connect.html new file mode 100644 index 0000000..b476980 --- /dev/null +++ b/doc/src/sgml/html/contrib-dblink-connect.html @@ -0,0 +1,105 @@ +<?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_connect</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="dblink.html" title="F.12. dblink" /><link rel="next" href="contrib-dblink-connect-u.html" title="dblink_connect_u" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">dblink_connect</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="dblink.html" title="F.12. dblink">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="dblink.html" title="F.12. dblink">Up</a></td><th width="60%" align="center">F.12. dblink</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 15.4 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="contrib-dblink-connect-u.html" title="dblink_connect_u">Next</a></td></tr></table><hr /></div><div class="refentry" id="CONTRIB-DBLINK-CONNECT"><div class="titlepage"></div><a id="id-1.11.7.21.5.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle">dblink_connect</span></h2><p>dblink_connect — opens a persistent connection to a remote database</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="synopsis"> +dblink_connect(text connstr) returns text +dblink_connect(text connname, text connstr) returns text +</pre></div><div class="refsect1" id="id-1.11.7.21.5.5"><h2>Description</h2><p> + <code class="function">dblink_connect()</code> establishes a connection to a remote + <span class="productname">PostgreSQL</span> database. The server and database to + be contacted are identified through a standard <span class="application">libpq</span> + connection string. Optionally, a name can be assigned to the + connection. Multiple named connections can be open at once, but + only one unnamed connection is permitted at a time. The connection + will persist until closed or until the database session is ended. + </p><p> + The connection string may also be the name of an existing foreign + server. It is recommended to use the foreign-data wrapper + <code class="literal">dblink_fdw</code> when defining the foreign + server. See the example below, as well as + <a class="xref" href="sql-createserver.html" title="CREATE SERVER"><span class="refentrytitle">CREATE SERVER</span></a> and + <a class="xref" href="sql-createusermapping.html" title="CREATE USER MAPPING"><span class="refentrytitle">CREATE USER MAPPING</span></a>. + </p></div><div class="refsect1" id="id-1.11.7.21.5.6"><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>connname</code></em></span></dt><dd><p> + The name to use for this connection; if omitted, an unnamed + connection is opened, replacing any existing unnamed connection. + </p></dd><dt><span class="term"><em class="parameter"><code>connstr</code></em></span></dt><dd><p><span class="application">libpq</span>-style connection info string, for example + <code class="literal">hostaddr=127.0.0.1 port=5432 dbname=mydb user=postgres + password=mypasswd options=-csearch_path=</code>. + For details see <a class="xref" href="libpq-connect.html#LIBPQ-CONNSTRING" title="34.1.1. Connection Strings">Section 34.1.1</a>. + Alternatively, the name of a foreign server. + </p></dd></dl></div></div><div class="refsect1" id="id-1.11.7.21.5.7"><h2>Return Value</h2><p> + Returns status, which is always <code class="literal">OK</code> (since any error + causes the function to throw an error instead of returning). + </p></div><div class="refsect1" id="id-1.11.7.21.5.8"><h2>Notes</h2><p> + If untrusted users have access to a database that has not adopted a + <a class="link" href="ddl-schemas.html#DDL-SCHEMAS-PATTERNS" title="5.9.6. Usage Patterns">secure schema usage pattern</a>, + begin each session by removing publicly-writable schemas from + <code class="varname">search_path</code>. One could, for example, + add <code class="literal">options=-csearch_path=</code> to + <em class="parameter"><code>connstr</code></em>. This consideration is not specific + to <code class="filename">dblink</code>; it applies to every interface for + executing arbitrary SQL commands. + </p><p> + Only superusers may use <code class="function">dblink_connect</code> to create + non-password-authenticated connections. If non-superusers need this + capability, use <code class="function">dblink_connect_u</code> instead. + </p><p> + It is unwise to choose connection names that contain equal signs, + as this opens a risk of confusion with connection info strings + in other <code class="filename">dblink</code> functions. + </p></div><div class="refsect1" id="id-1.11.7.21.5.9"><h2>Examples</h2><pre class="screen"> +SELECT dblink_connect('dbname=postgres options=-csearch_path='); + dblink_connect +---------------- + OK +(1 row) + +SELECT dblink_connect('myconn', 'dbname=postgres options=-csearch_path='); + dblink_connect +---------------- + OK +(1 row) + +-- FOREIGN DATA WRAPPER functionality +-- Note: local connection must require password authentication for this to work properly +-- Otherwise, you will receive the following error from dblink_connect(): +-- ERROR: password is required +-- DETAIL: Non-superuser cannot connect if the server does not request a password. +-- HINT: Target server's authentication method must be changed. + +CREATE SERVER fdtest FOREIGN DATA WRAPPER dblink_fdw OPTIONS (hostaddr '127.0.0.1', dbname 'contrib_regression'); + +CREATE USER regress_dblink_user WITH PASSWORD 'secret'; +CREATE USER MAPPING FOR regress_dblink_user SERVER fdtest OPTIONS (user 'regress_dblink_user', password 'secret'); +GRANT USAGE ON FOREIGN SERVER fdtest TO regress_dblink_user; +GRANT SELECT ON TABLE foo TO regress_dblink_user; + +\set ORIGINAL_USER :USER +\c - regress_dblink_user +SELECT dblink_connect('myconn', 'fdtest'); + dblink_connect +---------------- + OK +(1 row) + +SELECT * FROM dblink('myconn', 'SELECT * FROM foo') AS t(a int, b text, c text[]); + a | b | c +----+---+--------------- + 0 | a | {a0,b0,c0} + 1 | b | {a1,b1,c1} + 2 | c | {a2,b2,c2} + 3 | d | {a3,b3,c3} + 4 | e | {a4,b4,c4} + 5 | f | {a5,b5,c5} + 6 | g | {a6,b6,c6} + 7 | h | {a7,b7,c7} + 8 | i | {a8,b8,c8} + 9 | j | {a9,b9,c9} + 10 | k | {a10,b10,c10} +(11 rows) + +\c - :ORIGINAL_USER +REVOKE USAGE ON FOREIGN SERVER fdtest FROM regress_dblink_user; +REVOKE SELECT ON TABLE foo FROM regress_dblink_user; +DROP USER MAPPING FOR regress_dblink_user SERVER fdtest; +DROP USER regress_dblink_user; +DROP SERVER fdtest; +</pre></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="dblink.html" title="F.12. dblink">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="dblink.html" title="F.12. dblink">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="contrib-dblink-connect-u.html" title="dblink_connect_u">Next</a></td></tr><tr><td width="40%" align="left" valign="top">F.12. dblink </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 15.4 Documentation">Home</a></td><td width="40%" align="right" valign="top"> dblink_connect_u</td></tr></table></div></body></html>
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