ok
Direktori : /opt/alt/postgresql11/usr/share/doc/alt-postgresql11-9.2.24/html/ |
Current File : //opt/alt/postgresql11/usr/share/doc/alt-postgresql11-9.2.24/html/sql-createconversion.html |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >CREATE CONVERSION</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="SQL Commands" HREF="sql-commands.html"><LINK REL="PREVIOUS" TITLE="CREATE COLLATION" HREF="sql-createcollation.html"><LINK REL="NEXT" TITLE="CREATE DATABASE" HREF="sql-createdatabase.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="REFENTRY" ><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="CREATE COLLATION" HREF="sql-createcollation.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="sql-commands.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="20%" ALIGN="right" VALIGN="top" ><A TITLE="CREATE DATABASE" HREF="sql-createdatabase.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SQL-CREATECONVERSION" ></A >CREATE CONVERSION</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN67839" ></A ><H2 >Name</H2 >CREATE CONVERSION -- define a new encoding conversion</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN67844" ></A ><H2 >Synopsis</H2 ><PRE CLASS="SYNOPSIS" >CREATE [ DEFAULT ] CONVERSION <TT CLASS="REPLACEABLE" ><I >name</I ></TT > FOR <TT CLASS="REPLACEABLE" ><I >source_encoding</I ></TT > TO <TT CLASS="REPLACEABLE" ><I >dest_encoding</I ></TT > FROM <TT CLASS="REPLACEABLE" ><I >function_name</I ></TT ></PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="SQL-CREATECONVERSION-DESCRIPTION" ></A ><H2 >Description</H2 ><P > <TT CLASS="COMMAND" >CREATE CONVERSION</TT > defines a new conversion between character set encodings. Also, conversions that are marked <TT CLASS="LITERAL" >DEFAULT</TT > can be used for automatic encoding conversion between client and server. For this purpose, two conversions, from encoding A to B <SPAN CLASS="emphasis" ><I CLASS="EMPHASIS" >and</I ></SPAN > from encoding B to A, must be defined. </P ><P > To be able to create a conversion, you must have <TT CLASS="LITERAL" >EXECUTE</TT > privilege on the function and <TT CLASS="LITERAL" >CREATE</TT > privilege on the destination schema. </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN67859" ></A ><H2 >Parameters</H2 ><P ></P ><DIV CLASS="VARIABLELIST" ><DL ><DT ><TT CLASS="LITERAL" >DEFAULT</TT ></DT ><DD ><P > The <TT CLASS="LITERAL" >DEFAULT</TT > clause indicates that this conversion is the default for this particular source to destination encoding. There should be only one default encoding in a schema for the encoding pair. </P ></DD ><DT ><TT CLASS="REPLACEABLE" ><I >name</I ></TT ></DT ><DD ><P > The name of the conversion. The conversion name can be schema-qualified. If it is not, the conversion is defined in the current schema. The conversion name must be unique within a schema. </P ></DD ><DT ><TT CLASS="REPLACEABLE" ><I >source_encoding</I ></TT ></DT ><DD ><P > The source encoding name. </P ></DD ><DT ><TT CLASS="REPLACEABLE" ><I >dest_encoding</I ></TT ></DT ><DD ><P > The destination encoding name. </P ></DD ><DT ><TT CLASS="REPLACEABLE" ><I >function_name</I ></TT ></DT ><DD ><P > The function used to perform the conversion. The function name can be schema-qualified. If it is not, the function will be looked up in the path. </P ><P > The function must have the following signature: </P><PRE CLASS="PROGRAMLISTING" >conv_proc( integer, -- source encoding ID integer, -- destination encoding ID cstring, -- source string (null terminated C string) internal, -- destination (fill with a null terminated C string) integer -- source string length ) RETURNS void;</PRE ><P></P ></DD ></DL ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="SQL-CREATECONVERSION-NOTES" ></A ><H2 >Notes</H2 ><P > Use <TT CLASS="COMMAND" >DROP CONVERSION</TT > to remove user-defined conversions. </P ><P > The privileges required to create a conversion might be changed in a future release. </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="SQL-CREATECONVERSION-EXAMPLES" ></A ><H2 >Examples</H2 ><P > To create a conversion from encoding <TT CLASS="LITERAL" >UTF8</TT > to <TT CLASS="LITERAL" >LATIN1</TT > using <CODE CLASS="FUNCTION" >myfunc</CODE >: </P><PRE CLASS="PROGRAMLISTING" >CREATE CONVERSION myconv FOR 'UTF8' TO 'LATIN1' FROM myfunc;</PRE ><P></P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="SQL-CREATECONVERSION-COMPAT" ></A ><H2 >Compatibility</H2 ><P > <TT CLASS="COMMAND" >CREATE CONVERSION</TT > is a <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > extension. There is no <TT CLASS="COMMAND" >CREATE CONVERSION</TT > statement in the SQL standard, but a <TT CLASS="COMMAND" >CREATE TRANSLATION</TT > statement that is very similar in purpose and syntax. </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="SQL-CREATECONVERSION-SEEALSO" ></A ><H2 >See Also</H2 ><A HREF="sql-alterconversion.html" >ALTER CONVERSION</A >, <A HREF="sql-createfunction.html" >CREATE FUNCTION</A >, <A HREF="sql-dropconversion.html" >DROP CONVERSION</A ></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="sql-createcollation.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="sql-createdatabase.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >CREATE COLLATION</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="sql-commands.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >CREATE DATABASE</TD ></TR ></TABLE ></DIV ></BODY ></HTML >