<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >pg_class</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_cast" HREF="catalog-pg-cast.html"><LINK REL="NEXT" TITLE="pg_constraint" HREF="catalog-pg-constraint.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-cast.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-constraint.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="CATALOG-PG-CLASS" >41.9. <TT CLASS="STRUCTNAME" >pg_class</TT ></A ></H1 ><A NAME="AEN52696" ></A ><P > The catalog <TT CLASS="STRUCTNAME" >pg_class</TT > catalogs tables and most everything else that has columns or is otherwise similar to a table. This includes indexes (but see also <TT CLASS="STRUCTNAME" >pg_index</TT >), sequences, views, composite types, and some kinds of special relation; see <TT CLASS="STRUCTFIELD" >relkind</TT >. Below, when we mean all of these kinds of objects we speak of <SPAN CLASS="QUOTE" >"relations"</SPAN >. Not all columns are meaningful for all relation types. </P ><DIV CLASS="TABLE" ><A NAME="AEN52703" ></A ><P ><B >Table 41-9. <TT CLASS="STRUCTNAME" >pg_class</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" >relname</TT ></TD ><TD ><TT CLASS="TYPE" >name</TT ></TD ><TD > </TD ><TD >Name of the table, index, view, etc.</TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >relnamespace</TT ></TD ><TD ><TT CLASS="TYPE" >oid</TT ></TD ><TD ><TT CLASS="LITERAL" ><A HREF="catalog-pg-namespace.html" ><TT CLASS="STRUCTNAME" >pg_namespace</TT ></A >.oid</TT ></TD ><TD > The OID of the namespace that contains this relation </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >reltype</TT ></TD ><TD ><TT CLASS="TYPE" >oid</TT ></TD ><TD ><TT CLASS="LITERAL" ><A HREF="catalog-pg-type.html" ><TT CLASS="STRUCTNAME" >pg_type</TT ></A >.oid</TT ></TD ><TD > The OID of the data type that corresponds to this table's row type, if any (zero for indexes, which have no <TT CLASS="STRUCTNAME" >pg_type</TT > entry) </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >relowner</TT ></TD ><TD ><TT CLASS="TYPE" >int4</TT ></TD ><TD ><TT CLASS="LITERAL" ><A HREF="catalog-pg-shadow.html" ><TT CLASS="STRUCTNAME" >pg_shadow</TT ></A >.usesysid</TT ></TD ><TD >Owner of the relation</TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >relam</TT ></TD ><TD ><TT CLASS="TYPE" >oid</TT ></TD ><TD ><TT CLASS="LITERAL" ><A HREF="catalog-pg-am.html" ><TT CLASS="STRUCTNAME" >pg_am</TT ></A >.oid</TT ></TD ><TD >If this is an index, the access method used (B-tree, hash, etc.)</TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >relfilenode</TT ></TD ><TD ><TT CLASS="TYPE" >oid</TT ></TD ><TD > </TD ><TD >Name of the on-disk file of this relation; 0 if none</TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >reltablespace</TT ></TD ><TD ><TT CLASS="TYPE" >oid</TT ></TD ><TD ><TT CLASS="LITERAL" ><A HREF="catalog-pg-tablespace.html" ><TT CLASS="STRUCTNAME" >pg_tablespace</TT ></A >.oid</TT ></TD ><TD > The tablespace in which this relation is stored. If zero, the database's default tablespace is implied. (Not meaningful if the relation has no on-disk file.) </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >relpages</TT ></TD ><TD ><TT CLASS="TYPE" >int4</TT ></TD ><TD > </TD ><TD > Size of the on-disk representation of this table in pages (of size <TT CLASS="SYMBOL" >BLCKSZ</TT >). This is only an estimate used by the planner. It is updated by <TT CLASS="COMMAND" >VACUUM</TT >, <TT CLASS="COMMAND" >ANALYZE</TT >, and a few DDL commands such as <TT CLASS="COMMAND" >CREATE INDEX</TT >. </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >reltuples</TT ></TD ><TD ><TT CLASS="TYPE" >float4</TT ></TD ><TD > </TD ><TD > Number of rows in the table. This is only an estimate used by the planner. It is updated by <TT CLASS="COMMAND" >VACUUM</TT >, <TT CLASS="COMMAND" >ANALYZE</TT >, and a few DDL commands such as <TT CLASS="COMMAND" >CREATE INDEX</TT >. </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >reltoastrelid</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 > OID of the TOAST table associated with this table, 0 if none. The TOAST table stores large attributes <SPAN CLASS="QUOTE" >"out of line"</SPAN > in a secondary table. </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >reltoastidxid</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 > For a TOAST table, the OID of its index. 0 if not a TOAST table. </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >relhasindex</TT ></TD ><TD ><TT CLASS="TYPE" >bool</TT ></TD ><TD > </TD ><TD > True if this is a table and it has (or recently had) any indexes. This is set by <TT CLASS="COMMAND" >CREATE INDEX</TT >, but not cleared immediately by <TT CLASS="COMMAND" >DROP INDEX</TT >. <TT CLASS="COMMAND" >VACUUM</TT > clears <TT CLASS="STRUCTFIELD" >relhasindex</TT > if it finds the table has no indexes. </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >relisshared</TT ></TD ><TD ><TT CLASS="TYPE" >bool</TT ></TD ><TD > </TD ><TD >True if this table is shared across all databases in the cluster. Only certain system catalogs (such as <TT CLASS="STRUCTNAME" >pg_database</TT >) are shared.</TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >relkind</TT ></TD ><TD ><TT CLASS="TYPE" >char</TT ></TD ><TD > </TD ><TD > <TT CLASS="LITERAL" >r</TT > = ordinary table, <TT CLASS="LITERAL" >i</TT > = index, <TT CLASS="LITERAL" >S</TT > = sequence, <TT CLASS="LITERAL" >v</TT > = view, <TT CLASS="LITERAL" >c</TT > = composite type, <TT CLASS="LITERAL" >s</TT > = special, <TT CLASS="LITERAL" >t</TT > = TOAST table </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >relnatts</TT ></TD ><TD ><TT CLASS="TYPE" >int2</TT ></TD ><TD > </TD ><TD > Number of user columns in the relation (system columns not counted). There must be this many corresponding entries in <TT CLASS="STRUCTNAME" >pg_attribute</TT >. See also <TT CLASS="LITERAL" >pg_attribute.attnum</TT >. </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >relchecks</TT ></TD ><TD ><TT CLASS="TYPE" >int2</TT ></TD ><TD > </TD ><TD > Number of check constraints on the table; see <TT CLASS="STRUCTNAME" >pg_constraint</TT > catalog </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >reltriggers</TT ></TD ><TD ><TT CLASS="TYPE" >int2</TT ></TD ><TD > </TD ><TD > Number of triggers on the table; see <TT CLASS="STRUCTNAME" >pg_trigger</TT > catalog </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >relukeys</TT ></TD ><TD ><TT CLASS="TYPE" >int2</TT ></TD ><TD > </TD ><TD >unused (<SPAN CLASS="emphasis" ><I CLASS="EMPHASIS" >not</I ></SPAN > the number of unique keys)</TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >relfkeys</TT ></TD ><TD ><TT CLASS="TYPE" >int2</TT ></TD ><TD > </TD ><TD >unused (<SPAN CLASS="emphasis" ><I CLASS="EMPHASIS" >not</I ></SPAN > the number of foreign keys on the table)</TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >relrefs</TT ></TD ><TD ><TT CLASS="TYPE" >int2</TT ></TD ><TD > </TD ><TD >unused</TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >relhasoids</TT ></TD ><TD ><TT CLASS="TYPE" >bool</TT ></TD ><TD > </TD ><TD > True if we generate an OID for each row of the relation. </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >relhaspkey</TT ></TD ><TD ><TT CLASS="TYPE" >bool</TT ></TD ><TD > </TD ><TD > True if the table has (or once had) a primary key. </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >relhasrules</TT ></TD ><TD ><TT CLASS="TYPE" >bool</TT ></TD ><TD > </TD ><TD >True if table has rules; see <TT CLASS="STRUCTNAME" >pg_rewrite</TT > catalog. </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >relhassubclass</TT ></TD ><TD ><TT CLASS="TYPE" >bool</TT ></TD ><TD > </TD ><TD >True if table has (or once had) any inheritance children.</TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >relacl</TT ></TD ><TD ><TT CLASS="TYPE" >aclitem[]</TT ></TD ><TD > </TD ><TD > Access privileges; see <A HREF="sql-grant.html" ><I >GRANT</I ></A > and <A HREF="sql-revoke.html" ><I >REVOKE</I ></A > for details. </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="catalog-pg-cast.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-constraint.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><TT CLASS="STRUCTNAME" >pg_cast</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_constraint</TT ></TD ></TR ></TABLE ></DIV ></BODY ></HTML >