<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >pg_database</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 9.6.21 Documentation" HREF="index.html"><LINK REL="UP" TITLE="System Catalogs" HREF="catalogs.html"><LINK REL="PREVIOUS" TITLE="pg_conversion" HREF="catalog-pg-conversion.html"><LINK REL="NEXT" TITLE="pg_db_role_setting" HREF="catalog-pg-db-role-setting.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="2021-02-27T18:26:08"></HEAD ><BODY CLASS="SECT1" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="4" ALIGN="center" VALIGN="bottom" ><A HREF="index.html" >PostgreSQL 9.6.21 Documentation</A ></TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A TITLE="pg_conversion" HREF="catalog-pg-conversion.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="catalogs.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" >Chapter 50. System Catalogs</TD ><TD WIDTH="20%" ALIGN="right" VALIGN="top" ><A TITLE="pg_db_role_setting" HREF="catalog-pg-db-role-setting.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="CATALOG-PG-DATABASE" >50.15. <TT CLASS="STRUCTNAME" >pg_database</TT ></A ></H1 ><P > The catalog <TT CLASS="STRUCTNAME" >pg_database</TT > stores information about the available databases. Databases are created with the <A HREF="sql-createdatabase.html" >CREATE DATABASE</A > command. Consult <A HREF="managing-databases.html" >Chapter 22</A > for details about the meaning of some of the parameters. </P ><P > Unlike most system catalogs, <TT CLASS="STRUCTNAME" >pg_database</TT > is shared across all databases of a cluster: there is only one copy of <TT CLASS="STRUCTNAME" >pg_database</TT > per cluster, not one per database. </P ><DIV CLASS="TABLE" ><A NAME="AEN107274" ></A ><P ><B >Table 50-15. <TT CLASS="STRUCTNAME" >pg_database</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" >oid</TT ></TD ><TD ><TT CLASS="TYPE" >oid</TT ></TD ><TD > </TD ><TD >Row identifier (hidden attribute; must be explicitly selected)</TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >datname</TT ></TD ><TD ><TT CLASS="TYPE" >name</TT ></TD ><TD > </TD ><TD >Database name</TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >datdba</TT ></TD ><TD ><TT CLASS="TYPE" >oid</TT ></TD ><TD ><TT CLASS="LITERAL" ><A HREF="catalog-pg-authid.html" ><TT CLASS="STRUCTNAME" >pg_authid</TT ></A >.oid</TT ></TD ><TD >Owner of the database, usually the user who created it</TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >encoding</TT ></TD ><TD ><TT CLASS="TYPE" >int4</TT ></TD ><TD > </TD ><TD >Character encoding for this database (<CODE CLASS="FUNCTION" >pg_encoding_to_char()</CODE > can translate this number to the encoding name)</TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >datcollate</TT ></TD ><TD ><TT CLASS="TYPE" >name</TT ></TD ><TD > </TD ><TD >LC_COLLATE for this database</TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >datctype</TT ></TD ><TD ><TT CLASS="TYPE" >name</TT ></TD ><TD > </TD ><TD >LC_CTYPE for this database</TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >datistemplate</TT ></TD ><TD ><TT CLASS="TYPE" >bool</TT ></TD ><TD > </TD ><TD > If true, then this database can be cloned by any user with <TT CLASS="LITERAL" >CREATEDB</TT > privileges; if false, then only superusers or the owner of the database can clone it. </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >datallowconn</TT ></TD ><TD ><TT CLASS="TYPE" >bool</TT ></TD ><TD > </TD ><TD > If false then no one can connect to this database. This is used to protect the <TT CLASS="LITERAL" >template0</TT > database from being altered. </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >datconnlimit</TT ></TD ><TD ><TT CLASS="TYPE" >int4</TT ></TD ><TD > </TD ><TD > Sets maximum number of concurrent connections that can be made to this database. -1 means no limit. </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >datlastsysoid</TT ></TD ><TD ><TT CLASS="TYPE" >oid</TT ></TD ><TD > </TD ><TD > Last system OID in the database; useful particularly to <SPAN CLASS="APPLICATION" >pg_dump</SPAN > </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >datfrozenxid</TT ></TD ><TD ><TT CLASS="TYPE" >xid</TT ></TD ><TD > </TD ><TD > All transaction IDs before this one have been replaced with a permanent (<SPAN CLASS="QUOTE" >"frozen"</SPAN >) transaction ID in this database. This is used to track whether the database needs to be vacuumed in order to prevent transaction ID wraparound or to allow <TT CLASS="LITERAL" >pg_clog</TT > to be shrunk. It is the minimum of the per-table <TT CLASS="STRUCTNAME" >pg_class</TT >.<TT CLASS="STRUCTFIELD" >relfrozenxid</TT > values. </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >datminmxid</TT ></TD ><TD ><TT CLASS="TYPE" >xid</TT ></TD ><TD > </TD ><TD > All multixact IDs before this one have been replaced with a transaction ID in this database. This is used to track whether the database needs to be vacuumed in order to prevent multixact ID wraparound or to allow <TT CLASS="LITERAL" >pg_multixact</TT > to be shrunk. It is the minimum of the per-table <TT CLASS="STRUCTNAME" >pg_class</TT >.<TT CLASS="STRUCTFIELD" >relminmxid</TT > values. </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >dattablespace</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 default tablespace for the database. Within this database, all tables for which <TT CLASS="STRUCTNAME" >pg_class</TT >.<TT CLASS="STRUCTFIELD" >reltablespace</TT > is zero will be stored in this tablespace; in particular, all the non-shared system catalogs will be there. </TD ></TR ><TR ><TD ><TT CLASS="STRUCTFIELD" >datacl</TT ></TD ><TD ><TT CLASS="TYPE" >aclitem[]</TT ></TD ><TD > </TD ><TD > Access privileges; see <A HREF="sql-grant.html" >GRANT</A > and <A HREF="sql-revoke.html" >REVOKE</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-conversion.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-db-role-setting.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><TT CLASS="STRUCTNAME" >pg_conversion</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_db_role_setting</TT ></TD ></TR ></TABLE ></DIV ></BODY ></HTML >