MAINHACK

Viewing / Editing File: functions-enum.html

File is not writable. Editing disabled.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<HTML
><HEAD
><TITLE
>Enum Support 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="Functions and Operators"
HREF="functions.html"><LINK
REL="PREVIOUS"
TITLE="Date/Time Functions and Operators"
HREF="functions-datetime.html"><LINK
REL="NEXT"
TITLE="Geometric Functions and Operators"
HREF="functions-geometry.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="Date/Time Functions and Operators"
HREF="functions-datetime.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="top"
><A
HREF="functions.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="60%"
ALIGN="center"
VALIGN="bottom"
>Chapter 9. Functions and Operators</TD
><TD
WIDTH="20%"
ALIGN="right"
VALIGN="top"
><A
TITLE="Geometric Functions and Operators"
HREF="functions-geometry.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="FUNCTIONS-ENUM"
>9.10. Enum Support Functions</A
></H1
><P
>   For enum types (described in <A
HREF="datatype-enum.html"
>Section 8.7</A
>),
   there are several functions that allow cleaner programming without
   hard-coding particular values of an enum type.
   These are listed in <A
HREF="functions-enum.html#FUNCTIONS-ENUM-TABLE"
>Table 9-30</A
>. The examples
   assume an enum type created as:

</P><PRE
CLASS="PROGRAMLISTING"
>CREATE TYPE rainbow AS ENUM ('red', 'orange', 'yellow', 'green', 'blue', 'purple');</PRE
><P>

  </P
><DIV
CLASS="TABLE"
><A
NAME="FUNCTIONS-ENUM-TABLE"
></A
><P
><B
>Table 9-30. Enum Support Functions</B
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><COL><COL><COL><COL><THEAD
><TR
><TH
>Function</TH
><TH
>Description</TH
><TH
>Example</TH
><TH
>Example Result</TH
></TR
></THEAD
><TBODY
><TR
><TD
>         
         <TT
CLASS="LITERAL"
>enum_first(anyenum)</TT
>
       </TD
><TD
>Returns the first value of the input enum type</TD
><TD
><TT
CLASS="LITERAL"
>enum_first(null::rainbow)</TT
></TD
><TD
><TT
CLASS="LITERAL"
>red</TT
></TD
></TR
><TR
><TD
>         
         <TT
CLASS="LITERAL"
>enum_last(anyenum)</TT
>
       </TD
><TD
>Returns the last value of the input enum type</TD
><TD
><TT
CLASS="LITERAL"
>enum_last(null::rainbow)</TT
></TD
><TD
><TT
CLASS="LITERAL"
>purple</TT
></TD
></TR
><TR
><TD
>         
         <TT
CLASS="LITERAL"
>enum_range(anyenum)</TT
>
       </TD
><TD
>Returns all values of the input enum type in an ordered array</TD
><TD
><TT
CLASS="LITERAL"
>enum_range(null::rainbow)</TT
></TD
><TD
><TT
CLASS="LITERAL"
>{red,orange,yellow,green,blue,purple}</TT
></TD
></TR
><TR
><TD
ROWSPAN="3"
><TT
CLASS="LITERAL"
>enum_range(anyenum, anyenum)</TT
></TD
><TD
ROWSPAN="3"
>        Returns the range between the two given enum values, as an ordered
        array. The values must be from the same enum type. If the first
        parameter is null, the result will start with the first value of
        the enum type.
        If the second parameter is null, the result will end with the last
        value of the enum type.
       </TD
><TD
><TT
CLASS="LITERAL"
>enum_range('orange'::rainbow, 'green'::rainbow)</TT
></TD
><TD
><TT
CLASS="LITERAL"
>{orange,yellow,green}</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>enum_range(NULL, 'green'::rainbow)</TT
></TD
><TD
><TT
CLASS="LITERAL"
>{red,orange,yellow,green}</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>enum_range('orange'::rainbow, NULL)</TT
></TD
><TD
><TT
CLASS="LITERAL"
>{orange,yellow,green,blue,purple}</TT
></TD
></TR
></TBODY
></TABLE
></DIV
><P
>    Notice that except for the two-argument form of <CODE
CLASS="FUNCTION"
>enum_range</CODE
>,
    these functions disregard the specific value passed to them; they care
    only about its declared data type.  Either null or a specific value of
    the type can be passed, with the same result.  It is more common to
    apply these functions to a table column or function argument than to
    a hardwired type name as suggested by the examples.
   </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="functions-datetime.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="functions-geometry.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>Date/Time Functions and Operators</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="functions.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>Geometric Functions and Operators</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>
Cancel / Back
[ MAINHACK ]

Viewing / Editing File: functions-enum.html

Server Info

System Features

User Info
