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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-13 13:44:03 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-13 13:44:03 +0000 |
| commit | 293913568e6a7a86fd1479e1cff8e2ecb58d6568 (patch) | |
| tree | fc3b469a3ec5ab71b36ea97cc7aaddb838423a0c /doc/src/sgml/html/ddl-foreign-data.html | |
| parent | Initial commit. (diff) | |
| download | postgresql-16-293913568e6a7a86fd1479e1cff8e2ecb58d6568.tar.xz postgresql-16-293913568e6a7a86fd1479e1cff8e2ecb58d6568.zip | |
Adding upstream version 16.2.upstream/16.2
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'doc/src/sgml/html/ddl-foreign-data.html')
| -rw-r--r-- | doc/src/sgml/html/ddl-foreign-data.html | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/doc/src/sgml/html/ddl-foreign-data.html b/doc/src/sgml/html/ddl-foreign-data.html new file mode 100644 index 0000000..fe3be66 --- /dev/null +++ b/doc/src/sgml/html/ddl-foreign-data.html @@ -0,0 +1,41 @@ +<?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>5.12. Foreign Data</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="ddl-partitioning.html" title="5.11. Table Partitioning" /><link rel="next" href="ddl-others.html" title="5.13. Other Database Objects" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">5.12. Foreign Data</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="ddl-partitioning.html" title="5.11. Table Partitioning">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="ddl.html" title="Chapter 5. Data Definition">Up</a></td><th width="60%" align="center">Chapter 5. Data Definition</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 16.2 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="ddl-others.html" title="5.13. Other Database Objects">Next</a></td></tr></table><hr /></div><div class="sect1" id="DDL-FOREIGN-DATA"><div class="titlepage"><div><div><h2 class="title" style="clear: both">5.12. Foreign Data <a href="#DDL-FOREIGN-DATA" class="id_link">#</a></h2></div></div></div><a id="id-1.5.4.14.2" class="indexterm"></a><a id="id-1.5.4.14.3" class="indexterm"></a><a id="id-1.5.4.14.4" class="indexterm"></a><p> + <span class="productname">PostgreSQL</span> implements portions of the SQL/MED + specification, allowing you to access data that resides outside + PostgreSQL using regular SQL queries. Such data is referred to as + <em class="firstterm">foreign data</em>. (Note that this usage is not to be confused + with foreign keys, which are a type of constraint within the database.) + </p><p> + Foreign data is accessed with help from a + <em class="firstterm">foreign data wrapper</em>. A foreign data wrapper is a + library that can communicate with an external data source, hiding the + details of connecting to the data source and obtaining data from it. + There are some foreign data wrappers available as <code class="filename">contrib</code> + modules; see <a class="xref" href="contrib.html" title="Appendix F. Additional Supplied Modules and Extensions">Appendix F</a>. Other kinds of foreign data + wrappers might be found as third party products. If none of the existing + foreign data wrappers suit your needs, you can write your own; see <a class="xref" href="fdwhandler.html" title="Chapter 59. Writing a Foreign Data Wrapper">Chapter 59</a>. + </p><p> + To access foreign data, you need to create a <em class="firstterm">foreign server</em> + object, which defines how to connect to a particular external data source + according to the set of options used by its supporting foreign data + wrapper. Then you need to create one or more <em class="firstterm">foreign + tables</em>, which define the structure of the remote data. A + foreign table can be used in queries just like a normal table, but a + foreign table has no storage in the PostgreSQL server. Whenever it is + used, <span class="productname">PostgreSQL</span> asks the foreign data wrapper + to fetch data from the external source, or transmit data to the external + source in the case of update commands. + </p><p> + Accessing remote data may require authenticating to the external + data source. This information can be provided by a + <em class="firstterm">user mapping</em>, which can provide additional data + such as user names and passwords based + on the current <span class="productname">PostgreSQL</span> role. + </p><p> + For additional information, see + <a class="xref" href="sql-createforeigndatawrapper.html" title="CREATE FOREIGN DATA WRAPPER"><span class="refentrytitle">CREATE FOREIGN DATA WRAPPER</span></a>, + <a class="xref" href="sql-createserver.html" title="CREATE SERVER"><span class="refentrytitle">CREATE SERVER</span></a>, + <a class="xref" href="sql-createusermapping.html" title="CREATE USER MAPPING"><span class="refentrytitle">CREATE USER MAPPING</span></a>, + <a class="xref" href="sql-createforeigntable.html" title="CREATE FOREIGN TABLE"><span class="refentrytitle">CREATE FOREIGN TABLE</span></a>, and + <a class="xref" href="sql-importforeignschema.html" title="IMPORT FOREIGN SCHEMA"><span class="refentrytitle">IMPORT FOREIGN SCHEMA</span></a>. + </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ddl-partitioning.html" title="5.11. Table Partitioning">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ddl.html" title="Chapter 5. Data Definition">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ddl-others.html" title="5.13. Other Database Objects">Next</a></td></tr><tr><td width="40%" align="left" valign="top">5.11. Table Partitioning </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 16.2 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 5.13. Other Database Objects</td></tr></table></div></body></html>
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