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diff --git a/doc/src/sgml/html/xplang-install.html b/doc/src/sgml/html/xplang-install.html new file mode 100644 index 0000000..b1ec495 --- /dev/null +++ b/doc/src/sgml/html/xplang-install.html @@ -0,0 +1,142 @@ +<?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>42.1. Installing Procedural Languages</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="xplang.html" title="Chapter 42. Procedural Languages" /><link rel="next" href="plpgsql.html" title="Chapter 43. PL/pgSQL — SQL Procedural Language" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">42.1. Installing Procedural Languages</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="xplang.html" title="Chapter 42. Procedural Languages">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="xplang.html" title="Chapter 42. Procedural Languages">Up</a></td><th width="60%" align="center">Chapter 42. Procedural Languages</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 15.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="plpgsql.html" title="Chapter 43. PL/pgSQL — SQL Procedural Language">Next</a></td></tr></table><hr /></div><div class="sect1" id="XPLANG-INSTALL"><div class="titlepage"><div><div><h2 class="title" style="clear: both">42.1. Installing Procedural Languages</h2></div></div></div><p> + A procedural language must be <span class="quote">“<span class="quote">installed</span>”</span> into each + database where it is to be used. But procedural languages installed in + the database <code class="literal">template1</code> are automatically available in all + subsequently created databases, since their entries in + <code class="literal">template1</code> will be copied by <code class="command">CREATE DATABASE</code>. + So the database administrator can + decide which languages are available in which databases and can make + some languages available by default if desired. + </p><p> + For the languages supplied with the standard distribution, it is + only necessary to execute <code class="command">CREATE EXTENSION</code> + <em class="replaceable"><code>language_name</code></em> to install the language into the + current database. + The manual procedure described below is only recommended for + installing languages that have not been packaged as extensions. + </p><div class="procedure" id="id-1.8.7.5.4"><p class="title"><strong>Manual Procedural Language Installation</strong></p><p> + A procedural language is installed in a database in five steps, + which must be carried out by a database superuser. In most cases + the required SQL commands should be packaged as the installation script + of an <span class="quote">“<span class="quote">extension</span>”</span>, so that <code class="command">CREATE EXTENSION</code> can be + used to execute them. + </p><ol class="procedure" type="1"><li class="step" id="XPLANG-INSTALL-CR1"><p> + The shared object for the language handler must be compiled and + installed into an appropriate library directory. This works in the same + way as building and installing modules with regular user-defined C + functions does; see <a class="xref" href="xfunc-c.html#DFUNC" title="38.10.5. Compiling and Linking Dynamically-Loaded Functions">Section 38.10.5</a>. Often, the language + handler will depend on an external library that provides the actual + programming language engine; if so, that must be installed as well. + </p></li><li class="step" id="XPLANG-INSTALL-CR2"><p> + The handler must be declared with the command +</p><pre class="synopsis"> +CREATE FUNCTION <em class="replaceable"><code>handler_function_name</code></em>() + RETURNS language_handler + AS '<em class="replaceable"><code>path-to-shared-object</code></em>' + LANGUAGE C; +</pre><p> + The special return type of <code class="type">language_handler</code> tells + the database system that this function does not return one of + the defined <acronym class="acronym">SQL</acronym> data types and is not directly usable + in <acronym class="acronym">SQL</acronym> statements. + </p></li><li class="step" id="XPLANG-INSTALL-CR3"><p> + Optionally, the language handler can provide an <span class="quote">“<span class="quote">inline</span>”</span> + handler function that executes anonymous code blocks + (<a class="link" href="sql-do.html" title="DO"><code class="command">DO</code></a> commands) + written in this language. If an inline handler function + is provided by the language, declare it with a command like +</p><pre class="synopsis"> +CREATE FUNCTION <em class="replaceable"><code>inline_function_name</code></em>(internal) + RETURNS void + AS '<em class="replaceable"><code>path-to-shared-object</code></em>' + LANGUAGE C; +</pre><p> + </p></li><li class="step" id="XPLANG-INSTALL-CR4"><p> + Optionally, the language handler can provide a <span class="quote">“<span class="quote">validator</span>”</span> + function that checks a function definition for correctness without + actually executing it. The validator function is called by + <code class="command">CREATE FUNCTION</code> if it exists. If a validator function + is provided by the language, declare it with a command like +</p><pre class="synopsis"> +CREATE FUNCTION <em class="replaceable"><code>validator_function_name</code></em>(oid) + RETURNS void + AS '<em class="replaceable"><code>path-to-shared-object</code></em>' + LANGUAGE C STRICT; +</pre><p> + </p></li><li class="step" id="XPLANG-INSTALL-CR5"><p> + Finally, the PL must be declared with the command +</p><pre class="synopsis"> +CREATE [<span class="optional">TRUSTED</span>] LANGUAGE <em class="replaceable"><code>language_name</code></em> + HANDLER <em class="replaceable"><code>handler_function_name</code></em> + [<span class="optional">INLINE <em class="replaceable"><code>inline_function_name</code></em></span>] + [<span class="optional">VALIDATOR <em class="replaceable"><code>validator_function_name</code></em></span>] ; +</pre><p> + The optional key word <code class="literal">TRUSTED</code> specifies that + the language does not grant access to data that the user would + not otherwise have. Trusted languages are designed for ordinary + database users (those without superuser privilege) and allows them + to safely create functions and + procedures. Since PL functions are executed inside the database + server, the <code class="literal">TRUSTED</code> flag should only be given + for languages that do not allow access to database server + internals or the file system. The languages + <span class="application">PL/pgSQL</span>, + <span class="application">PL/Tcl</span>, and + <span class="application">PL/Perl</span> + are considered trusted; the languages + <span class="application">PL/TclU</span>, + <span class="application">PL/PerlU</span>, and + <span class="application">PL/PythonU</span> + are designed to provide unlimited functionality and should + <span class="emphasis"><em>not</em></span> be marked trusted. + </p></li></ol></div><p> + <a class="xref" href="xplang-install.html#XPLANG-INSTALL-EXAMPLE" title="Example 42.1. Manual Installation of PL/Perl">Example 42.1</a> shows how the manual + installation procedure would work with the language + <span class="application">PL/Perl</span>. + </p><div class="example" id="XPLANG-INSTALL-EXAMPLE"><p class="title"><strong>Example 42.1. Manual Installation of <span class="application">PL/Perl</span></strong></p><div class="example-contents"><p> + The following command tells the database server where to find the + shared object for the <span class="application">PL/Perl</span> language's call + handler function: + +</p><pre class="programlisting"> +CREATE FUNCTION plperl_call_handler() RETURNS language_handler AS + '$libdir/plperl' LANGUAGE C; +</pre><p> + </p><p> + <span class="application">PL/Perl</span> has an inline handler function + and a validator function, so we declare those too: + +</p><pre class="programlisting"> +CREATE FUNCTION plperl_inline_handler(internal) RETURNS void AS + '$libdir/plperl' LANGUAGE C STRICT; + +CREATE FUNCTION plperl_validator(oid) RETURNS void AS + '$libdir/plperl' LANGUAGE C STRICT; +</pre><p> + </p><p> + The command: +</p><pre class="programlisting"> +CREATE TRUSTED LANGUAGE plperl + HANDLER plperl_call_handler + INLINE plperl_inline_handler + VALIDATOR plperl_validator; +</pre><p> + then defines that the previously declared functions + should be invoked for functions and procedures where the + language attribute is <code class="literal">plperl</code>. + </p></div></div><br class="example-break" /><p> + In a default <span class="productname">PostgreSQL</span> installation, + the handler for the <span class="application">PL/pgSQL</span> language + is built and installed into the <span class="quote">“<span class="quote">library</span>”</span> + directory; furthermore, the <span class="application">PL/pgSQL</span> language + itself is installed in all databases. + If <span class="application">Tcl</span> support is configured in, the handlers for + <span class="application">PL/Tcl</span> and <span class="application">PL/TclU</span> are built and installed + in the library directory, but the language itself is not installed in any + database by default. + Likewise, the <span class="application">PL/Perl</span> and <span class="application">PL/PerlU</span> + handlers are built and installed if Perl support is configured, and the + <span class="application">PL/PythonU</span> handler is installed if Python support is + configured, but these languages are not installed by default. + </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="xplang.html" title="Chapter 42. Procedural Languages">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="xplang.html" title="Chapter 42. Procedural Languages">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="plpgsql.html" title="Chapter 43. PL/pgSQL — SQL Procedural Language">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 42. Procedural Languages </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 15.5 Documentation">Home</a></td><td width="40%" align="right" valign="top"> Chapter 43. <span class="application">PL/pgSQL</span> — <acronym class="acronym">SQL</acronym> Procedural Language</td></tr></table></div></body></html>
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