Mini Shell

Direktori : /proc/thread-self/root/opt/alt/postgresql11/usr/share/doc/alt-postgresql11-9.2.24/html/
Current File : //proc/thread-self/root/opt/alt/postgresql11/usr/share/doc/alt-postgresql11-9.2.24/html/xfunc.html
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<HTML
><HEAD
><TITLE
>User-defined Functions</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK
REV="MADE"
HREF="mailto:pgsql-docs@postgresql.org"><LINK
REL="HOME"
TITLE="PostgreSQL 9.2.24 Documentation"
HREF="index.html"><LINK
REL="UP"
TITLE="Extending SQL"
HREF="extend.html"><LINK
REL="PREVIOUS"
TITLE="The PostgreSQL Type System"
HREF="extend-type-system.html"><LINK
REL="NEXT"
TITLE="Query Language (SQL) Functions"
HREF="xfunc-sql.html"><LINK
REL="STYLESHEET"
TYPE="text/css"
HREF="stylesheet.css"><META
HTTP-EQUIV="Content-Type"
CONTENT="text/html; charset=ISO-8859-1"><META
NAME="creation"
CONTENT="2017-11-06T22:43:11"></HEAD
><BODY
CLASS="SECT1"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="5"
ALIGN="center"
VALIGN="bottom"
><A
HREF="index.html"
>PostgreSQL 9.2.24 Documentation</A
></TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="top"
><A
TITLE="The PostgreSQL Type System"
HREF="extend-type-system.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="top"
><A
HREF="extend.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="60%"
ALIGN="center"
VALIGN="bottom"
>Chapter 35. Extending <ACRONYM
CLASS="ACRONYM"
>SQL</ACRONYM
></TD
><TD
WIDTH="20%"
ALIGN="right"
VALIGN="top"
><A
TITLE="Query Language (SQL) Functions"
HREF="xfunc-sql.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="XFUNC"
>35.3. User-defined Functions</A
></H1
><P
>   <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> provides four kinds of
   functions:

   <P
></P
></P><UL
><LI
><P
>      query language functions (functions written in
      <ACRONYM
CLASS="ACRONYM"
>SQL</ACRONYM
>) (<A
HREF="xfunc-sql.html"
>Section 35.4</A
>)
     </P
></LI
><LI
><P
>      procedural language functions (functions written in, for
      example, <SPAN
CLASS="APPLICATION"
>PL/pgSQL</SPAN
> or <SPAN
CLASS="APPLICATION"
>PL/Tcl</SPAN
>)
      (<A
HREF="xfunc-pl.html"
>Section 35.7</A
>)
     </P
></LI
><LI
><P
>      internal functions (<A
HREF="xfunc-internal.html"
>Section 35.8</A
>)
     </P
></LI
><LI
><P
>      C-language functions (<A
HREF="xfunc-c.html"
>Section 35.9</A
>)
     </P
></LI
></UL
><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
HREF="sql-createfunction.html"
>CREATE FUNCTION</A
> command to
   understand the examples better.  Some examples from this chapter
   can be found in <TT
CLASS="FILENAME"
>funcs.sql</TT
> and
   <TT
CLASS="FILENAME"
>funcs.c</TT
> in the <TT
CLASS="FILENAME"
>src/tutorial</TT
>
   directory in the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> source
   distribution.
  </P
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="extend-type-system.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="index.html"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="xfunc-sql.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>The <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> Type System</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="extend.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>Query Language (<ACRONYM
CLASS="ACRONYM"
>SQL</ACRONYM
>) Functions</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>
Zerion Mini Shell 1.0