Sophie

Sophie

distrib > Mandriva > 2008.1 > x86_64 > media > main-testing > by-pkgid > bab02a23fa9f3df8d66a9a3231b50245 > files > 209

postgresql8.3-docs-8.3.6-2mdv2008.1.x86_64.rpm

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<HTML
><HEAD
><TITLE
>Binary String Functions and Operators</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 8.3.6 Documentation"
HREF="index.html"><LINK
REL="UP"
TITLE="Functions and Operators"
HREF="functions.html"><LINK
REL="PREVIOUS"
TITLE="String Functions and Operators"
HREF="functions-string.html"><LINK
REL="NEXT"
TITLE="Bit String Functions and Operators"
HREF="functions-bitstring.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="2009-02-03T04:34:16"></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"
>PostgreSQL 8.3.6 Documentation</TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="top"
><A
HREF="functions-string.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="top"
><A
HREF="functions.html"
>Fast Backward</A
></TD
><TD
WIDTH="60%"
ALIGN="center"
VALIGN="bottom"
>Chapter 9. Functions and Operators</TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="top"
><A
HREF="functions.html"
>Fast Forward</A
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="top"
><A
HREF="functions-bitstring.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="FUNCTIONS-BINARYSTRING"
>9.5. Binary String Functions and Operators</A
></H1
><A
NAME="AEN9237"
></A
><P
>    This section describes functions and operators for examining and
    manipulating values of type <TT
CLASS="TYPE"
>bytea</TT
>.
   </P
><P
>    <ACRONYM
CLASS="ACRONYM"
>SQL</ACRONYM
> defines some string functions with a
    special syntax where 
    certain key words rather than commas are used to separate the
    arguments.  Details are in
    <A
HREF="functions-binarystring.html#FUNCTIONS-BINARYSTRING-SQL"
>Table 9-8</A
>.
    Some functions are also implemented using the regular syntax for
    function invocation.
    (See <A
HREF="functions-binarystring.html#FUNCTIONS-BINARYSTRING-OTHER"
>Table 9-9</A
>.)
   </P
><DIV
CLASS="TABLE"
><A
NAME="FUNCTIONS-BINARYSTRING-SQL"
></A
><P
><B
>Table 9-8. <ACRONYM
CLASS="ACRONYM"
>SQL</ACRONYM
> Binary String Functions and Operators</B
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><COL><COL><COL><COL><COL><THEAD
><TR
><TH
>Function</TH
><TH
>Return Type</TH
><TH
>Description</TH
><TH
>Example</TH
><TH
>Result</TH
></TR
></THEAD
><TBODY
><TR
><TD
><TT
CLASS="LITERAL"
><TT
CLASS="PARAMETER"
>string</TT
> <TT
CLASS="LITERAL"
>||</TT
>
        <TT
CLASS="PARAMETER"
>string</TT
></TT
></TD
><TD
> <TT
CLASS="TYPE"
>bytea</TT
> </TD
><TD
>        String concatenation
        <A
NAME="AEN9267"
></A
>
       </TD
><TD
><TT
CLASS="LITERAL"
>E'\\\\Post'::bytea || E'\\047gres\\000'::bytea</TT
></TD
><TD
><TT
CLASS="LITERAL"
>\\Post'gres\000</TT
></TD
></TR
><TR
><TD
><CODE
CLASS="FUNCTION"
>get_bit</CODE
>(<TT
CLASS="PARAMETER"
>string</TT
>, <TT
CLASS="PARAMETER"
>offset</TT
>)</TD
><TD
><TT
CLASS="TYPE"
>int</TT
></TD
><TD
>        Extract bit from string
        <A
NAME="AEN9282"
></A
>
       </TD
><TD
><TT
CLASS="LITERAL"
>get_bit(E'Th\\000omas'::bytea, 45)</TT
></TD
><TD
><TT
CLASS="LITERAL"
>1</TT
></TD
></TR
><TR
><TD
><CODE
CLASS="FUNCTION"
>get_byte</CODE
>(<TT
CLASS="PARAMETER"
>string</TT
>, <TT
CLASS="PARAMETER"
>offset</TT
>)</TD
><TD
><TT
CLASS="TYPE"
>int</TT
></TD
><TD
>        Extract byte from string
        <A
NAME="AEN9296"
></A
>
       </TD
><TD
><TT
CLASS="LITERAL"
>get_byte(E'Th\\000omas'::bytea, 4)</TT
></TD
><TD
><TT
CLASS="LITERAL"
>109</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
><CODE
CLASS="FUNCTION"
>octet_length</CODE
>(<TT
CLASS="PARAMETER"
>string</TT
>)</TT
></TD
><TD
><TT
CLASS="TYPE"
>int</TT
></TD
><TD
>Number of bytes in binary string</TD
><TD
><TT
CLASS="LITERAL"
>octet_length(E'jo\\000se'::bytea)</TT
></TD
><TD
><TT
CLASS="LITERAL"
>5</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
><CODE
CLASS="FUNCTION"
>position</CODE
>(<TT
CLASS="PARAMETER"
>substring</TT
> in <TT
CLASS="PARAMETER"
>string</TT
>)</TT
></TD
><TD
><TT
CLASS="TYPE"
>int</TT
></TD
><TD
>Location of specified substring</TD
><TD
><TT
CLASS="LITERAL"
>position(E'\\000om'::bytea in E'Th\\000omas'::bytea)</TT
></TD
><TD
><TT
CLASS="LITERAL"
>3</TT
></TD
></TR
><TR
><TD
><CODE
CLASS="FUNCTION"
>set_bit</CODE
>(<TT
CLASS="PARAMETER"
>string</TT
>,
       <TT
CLASS="PARAMETER"
>offset</TT
>, <TT
CLASS="PARAMETER"
>newvalue</TT
>)</TD
><TD
><TT
CLASS="TYPE"
>bytea</TT
></TD
><TD
>        Set bit in string
        <A
NAME="AEN9336"
></A
>
       </TD
><TD
><TT
CLASS="LITERAL"
>set_bit(E'Th\\000omas'::bytea, 45, 0)</TT
></TD
><TD
><TT
CLASS="LITERAL"
>Th\000omAs</TT
></TD
></TR
><TR
><TD
><CODE
CLASS="FUNCTION"
>set_byte</CODE
>(<TT
CLASS="PARAMETER"
>string</TT
>,
       <TT
CLASS="PARAMETER"
>offset</TT
>, <TT
CLASS="PARAMETER"
>newvalue</TT
>)</TD
><TD
><TT
CLASS="TYPE"
>bytea</TT
></TD
><TD
>        Set byte in string
        <A
NAME="AEN9351"
></A
>
       </TD
><TD
><TT
CLASS="LITERAL"
>set_byte(E'Th\\000omas'::bytea, 4, 64)</TT
></TD
><TD
><TT
CLASS="LITERAL"
>Th\000o@as</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
><CODE
CLASS="FUNCTION"
>substring</CODE
>(<TT
CLASS="PARAMETER"
>string</TT
> [<SPAN
CLASS="OPTIONAL"
>from <TT
CLASS="TYPE"
>int</TT
></SPAN
>] [<SPAN
CLASS="OPTIONAL"
>for <TT
CLASS="TYPE"
>int</TT
></SPAN
>])</TT
></TD
><TD
><TT
CLASS="TYPE"
>bytea</TT
></TD
><TD
>        Extract substring
        <A
NAME="AEN9369"
></A
>
       </TD
><TD
><TT
CLASS="LITERAL"
>substring(E'Th\\000omas'::bytea from 2 for 3)</TT
></TD
><TD
><TT
CLASS="LITERAL"
>h\000o</TT
></TD
></TR
><TR
><TD
>        <TT
CLASS="LITERAL"
><CODE
CLASS="FUNCTION"
>trim</CODE
>([<SPAN
CLASS="OPTIONAL"
>both</SPAN
>]
        <TT
CLASS="PARAMETER"
>bytes</TT
> from
        <TT
CLASS="PARAMETER"
>string</TT
>)</TT
>
       </TD
><TD
><TT
CLASS="TYPE"
>bytea</TT
></TD
><TD
>        Remove the longest string containing only the bytes in
        <TT
CLASS="PARAMETER"
>bytes</TT
> from the start
        and end of <TT
CLASS="PARAMETER"
>string</TT
>
       </TD
><TD
><TT
CLASS="LITERAL"
>trim(E'\\000'::bytea from E'\\000Tom\\000'::bytea)</TT
></TD
><TD
><TT
CLASS="LITERAL"
>Tom</TT
></TD
></TR
></TBODY
></TABLE
></DIV
><P
>    Additional binary string manipulation functions are available and
    are listed in <A
HREF="functions-binarystring.html#FUNCTIONS-BINARYSTRING-OTHER"
>Table 9-9</A
>.  Some
    of them are used internally to implement the
    <ACRONYM
CLASS="ACRONYM"
>SQL</ACRONYM
>-standard string functions listed in <A
HREF="functions-binarystring.html#FUNCTIONS-BINARYSTRING-SQL"
>Table 9-8</A
>.
   </P
><DIV
CLASS="TABLE"
><A
NAME="FUNCTIONS-BINARYSTRING-OTHER"
></A
><P
><B
>Table 9-9. Other Binary String Functions</B
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><COL><COL><COL><COL><COL><THEAD
><TR
><TH
>Function</TH
><TH
>Return Type</TH
><TH
>Description</TH
><TH
>Example</TH
><TH
>Result</TH
></TR
></THEAD
><TBODY
><TR
><TD
><TT
CLASS="LITERAL"
><CODE
CLASS="FUNCTION"
>btrim</CODE
>(<TT
CLASS="PARAMETER"
>string</TT
>
        <TT
CLASS="TYPE"
>bytea</TT
>, <TT
CLASS="PARAMETER"
>bytes</TT
> <TT
CLASS="TYPE"
>bytea</TT
>)</TT
></TD
><TD
><TT
CLASS="TYPE"
>bytea</TT
></TD
><TD
>        Remove the longest string consisting only of bytes
        in <TT
CLASS="PARAMETER"
>bytes</TT
> from the start and end of
        <TT
CLASS="PARAMETER"
>string</TT
>
      </TD
><TD
><TT
CLASS="LITERAL"
>btrim(E'\\000trim\\000'::bytea, E'\\000'::bytea)</TT
></TD
><TD
><TT
CLASS="LITERAL"
>trim</TT
></TD
></TR
><TR
><TD
>       <TT
CLASS="LITERAL"
><CODE
CLASS="FUNCTION"
>decode</CODE
>(<TT
CLASS="PARAMETER"
>string</TT
> <TT
CLASS="TYPE"
>text</TT
>,
              <TT
CLASS="PARAMETER"
>type</TT
> <TT
CLASS="TYPE"
>text</TT
>)</TT
>
      </TD
><TD
><TT
CLASS="TYPE"
>bytea</TT
></TD
><TD
>       Decode binary string from <TT
CLASS="PARAMETER"
>string</TT
> previously 
       encoded with <CODE
CLASS="FUNCTION"
>encode</CODE
>.  Parameter type is same as in <CODE
CLASS="FUNCTION"
>encode</CODE
>.
      </TD
><TD
><TT
CLASS="LITERAL"
>decode(E'123\\000456', 'escape')</TT
></TD
><TD
><TT
CLASS="LITERAL"
>123\000456</TT
></TD
></TR
><TR
><TD
>       <TT
CLASS="LITERAL"
><CODE
CLASS="FUNCTION"
>encode</CODE
>(<TT
CLASS="PARAMETER"
>string</TT
> <TT
CLASS="TYPE"
>bytea</TT
>,
              <TT
CLASS="PARAMETER"
>type</TT
> <TT
CLASS="TYPE"
>text</TT
>)</TT
>
      </TD
><TD
><TT
CLASS="TYPE"
>text</TT
></TD
><TD
>       Encode binary string to <ACRONYM
CLASS="ACRONYM"
>ASCII</ACRONYM
>-only representation.  Supported
       types are: <TT
CLASS="LITERAL"
>base64</TT
>, <TT
CLASS="LITERAL"
>hex</TT
>, <TT
CLASS="LITERAL"
>escape</TT
>.
      </TD
><TD
><TT
CLASS="LITERAL"
>encode(E'123\\000456'::bytea, 'escape')</TT
></TD
><TD
><TT
CLASS="LITERAL"
>123\000456</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
><CODE
CLASS="FUNCTION"
>length</CODE
>(<TT
CLASS="PARAMETER"
>string</TT
>)</TT
></TD
><TD
><TT
CLASS="TYPE"
>int</TT
></TD
><TD
>       Length of binary string
       <A
NAME="AEN9468"
></A
>
       <A
NAME="AEN9471"
></A
>
      </TD
><TD
><TT
CLASS="LITERAL"
>length(E'jo\\000se'::bytea)</TT
></TD
><TD
><TT
CLASS="LITERAL"
>5</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
><CODE
CLASS="FUNCTION"
>md5</CODE
>(<TT
CLASS="PARAMETER"
>string</TT
>)</TT
></TD
><TD
><TT
CLASS="TYPE"
>text</TT
></TD
><TD
>       Calculates the MD5 hash of <TT
CLASS="PARAMETER"
>string</TT
>,
       returning the result in hexadecimal
      </TD
><TD
><TT
CLASS="LITERAL"
>md5(E'Th\\000omas'::bytea)</TT
></TD
><TD
><TT
CLASS="LITERAL"
>8ab2d3c9689aaf18 b4958c334c82d8b1</TT
></TD
></TR
></TBODY
></TABLE
></DIV
></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-string.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-bitstring.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>String 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"
>Bit String Functions and Operators</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>

Perl :: Catalyst :: PostgreSQL :: RPM Valid HTML 4.01 Transitional