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/ecpg-sql-whenever.html |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >WHENEVER</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="Embedded SQL Commands" HREF="ecpg-sql-commands.html"><LINK REL="PREVIOUS" TITLE="VAR" HREF="ecpg-sql-var.html"><LINK REL="NEXT" TITLE="Informix Compatibility Mode" HREF="ecpg-informix-compat.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="VAR" HREF="ecpg-sql-var.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="ecpg-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="Informix Compatibility Mode" HREF="ecpg-informix-compat.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="ECPG-SQL-WHENEVER" ></A >WHENEVER</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN45841" ></A ><H2 >Name</H2 >WHENEVER -- specify the action to be taken when an SQL statement causes a specific class condition to be raised</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN45844" ></A ><H2 >Synopsis</H2 ><PRE CLASS="SYNOPSIS" >WHENEVER { NOT FOUND | SQLERROR | SQLWARNING } <TT CLASS="REPLACEABLE" ><I >action</I ></TT ></PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN45847" ></A ><H2 >Description</H2 ><P > Define a behavior which is called on the special cases (Rows not found, SQL warnings or errors) in the result of SQL execution. </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN45850" ></A ><H2 >Parameters</H2 ><P > See <A HREF="ecpg-errors.html#ECPG-WHENEVER" >Section 33.8.1</A > for a description of the parameters. </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN45854" ></A ><H2 >Examples</H2 ><PRE CLASS="PROGRAMLISTING" >EXEC SQL WHENEVER NOT FOUND CONTINUE; EXEC SQL WHENEVER NOT FOUND DO BREAK; EXEC SQL WHENEVER SQLWARNING SQLPRINT; EXEC SQL WHENEVER SQLWARNING DO warn(); EXEC SQL WHENEVER SQLERROR sqlprint; EXEC SQL WHENEVER SQLERROR CALL print2(); EXEC SQL WHENEVER SQLERROR DO handle_error("select"); EXEC SQL WHENEVER SQLERROR DO sqlnotice(NULL, NONO); EXEC SQL WHENEVER SQLERROR DO sqlprint(); EXEC SQL WHENEVER SQLERROR GOTO error_label; EXEC SQL WHENEVER SQLERROR STOP;</PRE ><P > A typical application is the use of <TT CLASS="LITERAL" >WHENEVER NOT FOUND BREAK</TT > to handle looping through result sets: </P><PRE CLASS="PROGRAMLISTING" >int main(void) { EXEC SQL CONNECT TO testdb AS con1; EXEC SQL ALLOCATE DESCRIPTOR d; EXEC SQL DECLARE cur CURSOR FOR SELECT current_database(), 'hoge', 256; EXEC SQL OPEN cur; /* when end of result set reached, break out of while loop */ EXEC SQL WHENEVER NOT FOUND DO BREAK; while (1) { EXEC SQL FETCH NEXT FROM cur INTO SQL DESCRIPTOR d; ... } EXEC SQL CLOSE cur; EXEC SQL COMMIT; EXEC SQL DEALLOCATE DESCRIPTOR d; EXEC SQL DISCONNECT ALL; return 0; }</PRE ><P> </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN45860" ></A ><H2 >Compatibility</H2 ><P > <TT CLASS="COMMAND" >WHENEVER</TT > is specified in the SQL standard, but most of the actions are PostgreSQL extensions. </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="ecpg-sql-var.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="ecpg-informix-compat.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >VAR</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="ecpg-sql-commands.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><SPAN CLASS="PRODUCTNAME" >Informix</SPAN > Compatibility Mode</TD ></TR ></TABLE ></DIV ></BODY ></HTML >