<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >pg_attrdef</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="System Catalogs" HREF="catalogs.html"><LINK REL="PREVIOUS" TITLE="pg_amproc" HREF="catalog-pg-amproc.html"><LINK REL="NEXT" TITLE="pg_attribute" HREF="catalog-pg-attribute.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="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 8.0.11 Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="catalog-pg-amproc.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="catalogs.html" >Fast Backward</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" >Chapter 41. System Catalogs</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="catalogs.html" >Fast Forward</A ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="catalog-pg-attribute.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="CATALOG-PG-ATTRDEF" >41.6. <TT CLASS="STRUCTNAME" >pg_attrdef</TT ></A ></H1 ><A NAME="AEN52399" ></A ><P > The catalog <TT CLASS="STRUCTNAME" >pg_attrdef</TT > stores column default values. The main information about columns is stored in <TT CLASS="STRUCTNAME" >pg_attribute</TT > (see below). Only columns that explicitly specify a default value (when the table is created or the column is added) will have an entry here. </P ><DIV CLASS="TABLE" ><A NAME="AEN52404" ></A ><P ><B >Table 41-6. <TT CLASS="STRUCTNAME" >pg_attrdef</TT > Columns</B ></P ><TABLE BORDER="1" CLASS="CALSTABLE" ><COL><COL><COL><COL><THEAD ><TR ><TH >Name</TH ><TH >Type</TH ><TH >References</TH ><TH >Description</TH ></TR ></THEAD ><TBODY ><TR ><TD ><TT CLASS="STRUCTFIELD" >adrelid</TT ></TD ><TD ><TT CLASS="TYPE" >oid</TT ></TD ><TD ><TT CLASS="LITERAL" ><A HREF="catalog-pg-class.html" ><TT CLASS="STRUCTNAME" >pg_class</TT ></A >.oid</TT ></TD ><TD >The table this column belongs to</TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >adnum</TT ></TD ><TD ><TT CLASS="TYPE" >int2</TT ></TD ><TD ><TT CLASS="LITERAL" ><A HREF="catalog-pg-attribute.html" ><TT CLASS="STRUCTNAME" >pg_attribute</TT ></A >.attnum</TT ></TD ><TD >The number of the column</TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >adbin</TT ></TD ><TD ><TT CLASS="TYPE" >text</TT ></TD ><TD > </TD ><TD >The internal representation of the column default value</TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >adsrc</TT ></TD ><TD ><TT CLASS="TYPE" >text</TT ></TD ><TD > </TD ><TD >A human-readable representation of the default value</TD ></TR ></TBODY ></TABLE ></DIV ><P > The <TT CLASS="STRUCTFIELD" >adsrc</TT > field is historical, and is best not used, because it does not track outside changes that might affect the representation of the default value. Reverse-compiling the <TT CLASS="STRUCTFIELD" >adbin</TT > field (with <CODE CLASS="FUNCTION" >pg_get_expr</CODE > for example) is a better way to display the default value. </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="catalog-pg-amproc.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="catalog-pg-attribute.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><TT CLASS="STRUCTNAME" >pg_amproc</TT ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="catalogs.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><TT CLASS="STRUCTNAME" >pg_attribute</TT ></TD ></TR ></TABLE ></DIV ></BODY ></HTML >