<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >TRUNCATE</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 8.0.11 Documentation" HREF="index.html"><LINK REL="UP" TITLE="SQL Commands" HREF="sql-commands.html"><LINK REL="PREVIOUS" TITLE="START TRANSACTION" HREF="sql-start-transaction.html"><LINK REL="NEXT" TITLE="UNLISTEN" HREF="sql-unlisten.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="2007-02-02T03:57:22"></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" >PostgreSQL 8.0.11 Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="sql-start-transaction.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="sql-start-transaction.html" >Fast Backward</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="sql-unlisten.html" >Fast Forward</A ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="sql-unlisten.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SQL-TRUNCATE" ></A >TRUNCATE</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN45755" ></A ><H2 >Name</H2 >TRUNCATE -- empty a table</DIV ><A NAME="AEN45758" ></A ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN45760" ></A ><H2 >Synopsis</H2 ><PRE CLASS="SYNOPSIS" >TRUNCATE [ TABLE ] <TT CLASS="REPLACEABLE" ><I >name</I ></TT ></PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN45763" ></A ><H2 >Description</H2 ><P > <TT CLASS="COMMAND" >TRUNCATE</TT > quickly removes all rows from a table. It has the same effect as an unqualified <TT CLASS="COMMAND" >DELETE</TT > but since it does not actually scan the table it is faster. This is most useful on large tables. </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN45768" ></A ><H2 >Parameters</H2 ><P ></P ><DIV CLASS="VARIABLELIST" ><DL ><DT ><TT CLASS="REPLACEABLE" ><I >name</I ></TT ></DT ><DD ><P > The name (optionally schema-qualified) of the table to be truncated. </P ></DD ></DL ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN45776" ></A ><H2 >Notes</H2 ><P > Only the owner of a table may <TT CLASS="COMMAND" >TRUNCATE</TT > it. </P ><P > <TT CLASS="COMMAND" >TRUNCATE</TT > cannot be used if there are foreign-key references to the table from other tables. Checking validity in such cases would require table scans, and the whole point is not to do one. </P ><P > <TT CLASS="COMMAND" >TRUNCATE</TT > will not run any user-defined <TT CLASS="LITERAL" >ON DELETE</TT > triggers that might exist for the table. </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN45785" ></A ><H2 >Examples</H2 ><P > Truncate the table <TT CLASS="LITERAL" >bigtable</TT >: </P><PRE CLASS="PROGRAMLISTING" >TRUNCATE TABLE bigtable;</PRE ><P> </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN45790" ></A ><H2 >Compatibility</H2 ><P > There is no <TT CLASS="COMMAND" >TRUNCATE</TT > command in the SQL standard. </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="sql-start-transaction.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-unlisten.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >START TRANSACTION</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" >UNLISTEN</TD ></TR ></TABLE ></DIV ></BODY ></HTML >