<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >constraint_column_usage</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="The Information Schema" HREF="information-schema.html"><LINK REL="PREVIOUS" TITLE="columns" HREF="infoschema-columns.html"><LINK REL="NEXT" TITLE="constraint_table_usage" HREF="infoschema-constraint-table-usage.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="infoschema-columns.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="information-schema.html" >Fast Backward</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" >Chapter 30. The Information Schema</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="information-schema.html" >Fast Forward</A ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="infoschema-constraint-table-usage.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="INFOSCHEMA-CONSTRAINT-COLUMN-USAGE" >30.10. <TT CLASS="LITERAL" >constraint_column_usage</TT ></A ></H1 ><P > The view <TT CLASS="LITERAL" >constraint_column_usage</TT > identifies all columns in the current database that are used by some constraint. Only those columns are shown that are contained in a table owned the current user. For a check constraint, this view identifies the columns that are used in the check expression. For a foreign key constraint, this view identifies the columns that the foreign key references. For a unique or primary key constraint, this view identifies the constrained columns. </P ><DIV CLASS="TABLE" ><A NAME="AEN26535" ></A ><P ><B >Table 30-8. <TT CLASS="LITERAL" >constraint_column_usage</TT > Columns</B ></P ><TABLE BORDER="1" CLASS="CALSTABLE" ><COL><COL><COL><THEAD ><TR ><TH >Name</TH ><TH >Data Type</TH ><TH >Description</TH ></TR ></THEAD ><TBODY ><TR ><TD ><TT CLASS="LITERAL" >table_catalog</TT ></TD ><TD ><TT CLASS="TYPE" >sql_identifier</TT ></TD ><TD > Name of the database that contains the table that contains the column that is used by some constraint (always the current database) </TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >table_schema</TT ></TD ><TD ><TT CLASS="TYPE" >sql_identifier</TT ></TD ><TD > Name of the schema that contains the table that contains the column that is used by some constraint </TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >table_name</TT ></TD ><TD ><TT CLASS="TYPE" >sql_identifier</TT ></TD ><TD > Name of the table that contains the column that is used by some constraint </TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >column_name</TT ></TD ><TD ><TT CLASS="TYPE" >sql_identifier</TT ></TD ><TD > Name of the column that is used by some constraint </TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >constraint_catalog</TT ></TD ><TD ><TT CLASS="TYPE" >sql_identifier</TT ></TD ><TD >Name of the database that contains the constraint (always the current database)</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >constraint_schema</TT ></TD ><TD ><TT CLASS="TYPE" >sql_identifier</TT ></TD ><TD >Name of the schema that contains the constraint</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >constraint_name</TT ></TD ><TD ><TT CLASS="TYPE" >sql_identifier</TT ></TD ><TD >Name of the constraint</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="infoschema-columns.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="infoschema-constraint-table-usage.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><TT CLASS="LITERAL" >columns</TT ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="information-schema.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><TT CLASS="LITERAL" >constraint_table_usage</TT ></TD ></TR ></TABLE ></DIV ></BODY ></HTML >