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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:17:33 +0000 |
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| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:17:33 +0000 |
| commit | 5e45211a64149b3c659b90ff2de6fa982a5a93ed (patch) | |
| tree | 739caf8c461053357daa9f162bef34516c7bf452 /doc/src/sgml/html/xfunc.html | |
| parent | Initial commit. (diff) | |
| download | postgresql-15-5e45211a64149b3c659b90ff2de6fa982a5a93ed.tar.xz postgresql-15-5e45211a64149b3c659b90ff2de6fa982a5a93ed.zip | |
Adding upstream version 15.5.upstream/15.5
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'doc/src/sgml/html/xfunc.html')
| -rw-r--r-- | doc/src/sgml/html/xfunc.html | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/doc/src/sgml/html/xfunc.html b/doc/src/sgml/html/xfunc.html new file mode 100644 index 0000000..2017086 --- /dev/null +++ b/doc/src/sgml/html/xfunc.html @@ -0,0 +1,43 @@ +<?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>38.3. User-Defined Functions</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="extend-type-system.html" title="38.2. The PostgreSQL Type System" /><link rel="next" href="xproc.html" title="38.4. User-Defined Procedures" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">38.3. User-Defined Functions</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="extend-type-system.html" title="38.2. The PostgreSQL Type System">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="extend.html" title="Chapter 38. Extending SQL">Up</a></td><th width="60%" align="center">Chapter 38. Extending <acronym class="acronym">SQL</acronym></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="xproc.html" title="38.4. User-Defined Procedures">Next</a></td></tr></table><hr /></div><div class="sect1" id="XFUNC"><div class="titlepage"><div><div><h2 class="title" style="clear: both">38.3. User-Defined Functions</h2></div></div></div><a id="id-1.8.3.6.2" class="indexterm"></a><p> + <span class="productname">PostgreSQL</span> provides four kinds of + functions: + + </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p> + query language functions (functions written in + <acronym class="acronym">SQL</acronym>) (<a class="xref" href="xfunc-sql.html" title="38.5. Query Language (SQL) Functions">Section 38.5</a>) + </p></li><li class="listitem"><p> + procedural language functions (functions written in, for + example, <span class="application">PL/pgSQL</span> or <span class="application">PL/Tcl</span>) + (<a class="xref" href="xfunc-pl.html" title="38.8. Procedural Language Functions">Section 38.8</a>) + </p></li><li class="listitem"><p> + internal functions (<a class="xref" href="xfunc-internal.html" title="38.9. Internal Functions">Section 38.9</a>) + </p></li><li class="listitem"><p> + C-language functions (<a class="xref" href="xfunc-c.html" title="38.10. C-Language Functions">Section 38.10</a>) + </p></li></ul></div><p> + </p><p> + Every kind + of function can take base types, composite types, or + combinations of these as arguments (parameters). In addition, + every kind of function can return a base type or + a composite type. Functions can also be defined to return + sets of base or composite values. + </p><p> + Many kinds of functions can take or return certain pseudo-types + (such as polymorphic types), but the available facilities vary. + Consult the description of each kind of function for more details. + </p><p> + It's easiest to define <acronym class="acronym">SQL</acronym> + functions, so we'll start by discussing those. + Most of the concepts presented for <acronym class="acronym">SQL</acronym> functions + will carry over to the other types of functions. + </p><p> + Throughout this chapter, it can be useful to look at the reference + page of the <a class="link" href="sql-createfunction.html" title="CREATE FUNCTION"><code class="command">CREATE + FUNCTION</code></a> command to + understand the examples better. Some examples from this chapter + can be found in <code class="filename">funcs.sql</code> and + <code class="filename">funcs.c</code> in the <code class="filename">src/tutorial</code> + directory in the <span class="productname">PostgreSQL</span> source + distribution. + </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="extend-type-system.html" title="38.2. The PostgreSQL Type System">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="extend.html" title="Chapter 38. Extending SQL">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="xproc.html" title="38.4. User-Defined Procedures">Next</a></td></tr><tr><td width="40%" align="left" valign="top">38.2. The <span class="productname">PostgreSQL</span> Type System </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"> 38.4. User-Defined Procedures</td></tr></table></div></body></html>
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