diff --git a/phpcs.xml b/phpcs.xml
index a69d48c7..af3d3450 100644
--- a/phpcs.xml
+++ b/phpcs.xml
@@ -58,6 +58,7 @@
 			<property name="lineLimit" value="250"/>
 		</properties>
 		<exclude-pattern>adminer/lang/</exclude-pattern>
+		<exclude-pattern>plugins/foreign-system.php</exclude-pattern>
 		<exclude-pattern>plugins/select-email.php</exclude-pattern>
 	</rule>
 
diff --git a/plugins/foreign-system.php b/plugins/foreign-system.php
index fc26f221..82275877 100644
--- a/plugins/foreign-system.php
+++ b/plugins/foreign-system.php
@@ -1,6 +1,6 @@
 <?php
 
-/** Link system tables (in "mysql" and "information_schema" databases) by foreign keys
+/** Link system tables (in "mysql", "information_schema" and "pg_catalog" schemas) by foreign keys
 * @link https://www.adminer.org/plugins/#use
 * @author Jakub Vrana, https://www.vrana.cz/
 * @license https://www.apache.org/licenses/LICENSE-2.0 Apache License, Version 2.0
@@ -29,7 +29,8 @@ class AdminerForeignSystem extends Adminer\Plugin {
 				"time_zone_transition_type" => array(array("table" => "time_zone", "source" => array("Time_zone_id"), "target" => array("Time_zone_id"))),
 			);
 			return $return[$table];
-		} elseif (Adminer\DB == "information_schema") {
+
+		} elseif (Adminer\DB == "information_schema" || $_GET["ns"] == "information_schema") {
 			$schemata = $this->schemata("TABLE");
 			$tables = $this->tables("TABLE");
 			$columns = array("table" => "COLUMNS", "source" => array("TABLE_CATALOG", "TABLE_SCHEMA", "TABLE_NAME", "COLUMN_NAME"), "target" => array("TABLE_CATALOG", "TABLE_SCHEMA", "TABLE_NAME", "COLUMN_NAME"));
@@ -85,10 +86,88 @@ class AdminerForeignSystem extends Adminer\Plugin {
 				"VIEWS" => array($schemata, $this->character_sets("CHARACTER_SET_CLIENT"), $this->collations("COLLATION_CONNECTION")),
 				"VIEW_TABLE_USAGE" => array($schemata, $this->schemata("VIEW"), $tables, array("table" => "VIEWS", "source" => array("VIEW_CATALOG", "VIEW_SCHEMA", "VIEW_NAME"), "target" => array("TABLE_CATALOG", "TABLE_SCHEMA", "TABLE_NAME"))),
 			);
-			return $return[$table];
+			if ($_GET["ns"] == "information_schema") {
+				$return = $this->lowerCase($return);
+			}
+			return $return[strtoupper($table)];
+
+		} elseif (Adminer\DRIVER == "pgsql" && $_GET["ns"] == "pg_catalog") {
+			$mapping = array(
+				'pg_aggregate' => array('aggfnoid.proc', 'aggtransfn.proc', 'aggfinalfn.proc', 'aggcombinefn.proc', 'aggserialfn.proc', 'aggdeserialfn.proc', 'aggmtransfn.proc', 'aggminvtransfn.proc', 'aggmfinalfn.proc', 'aggsortop.operator', 'aggtranstype.type', 'aggmtranstype.type'),
+				'pg_am' => array('amhandler.proc'),
+				'pg_amop' => array('amopfamily.opfamily', 'amoplefttype.type', 'amoprighttype.type', 'amopopr.operator', 'amopmethod.am', 'amopsortfamily.opfamily'),
+				'pg_amproc' => array('amprocfamily.opfamily', 'amproclefttype.type', 'amprocrighttype.type', 'amproc.proc'),
+				'pg_attrdef' => array('adrelid.class', 'adnum.attribute.attnum'),
+				'pg_attribute' => array('attrelid.class', 'atttypid.type', 'attcollation.collation'),
+				'pg_auth_members' => array('roleid.authid', 'member.authid', 'grantor.authid'),
+				'pg_cast' => array('castsource.type', 'casttarget.type', 'castfunc.proc'),
+				'pg_class' => array('relnamespace.namespace', 'reltype.type', 'reloftype.type', 'relowner.authid', 'relam.am', 'reltablespace.tablespace', 'reltoastrelid.class', 'relrewrite.class'),
+				'pg_collation' => array('collnamespace.namespace', 'collowner.authid'),
+				'pg_constraint' => array('connamespace.namespace', 'conrelid.class', 'contypid.type', 'conindid.class', 'conparentid.constraint', 'confrelid.class', 'conkey.attribute.attnum', 'confkey.attribute.attnum', 'conpfeqop.operator', 'conppeqop.operator', 'conffeqop.operator', 'confdelsetcols.attribute.attnum', 'conexclop.operator'),
+				'pg_conversion' => array('connamespace.namespace', 'conowner.authid', 'conproc.proc'),
+				'pg_database' => array('datdba.authid', 'dattablespace.tablespace'),
+				'pg_db_role_setting' => array('setdatabase.database', 'setrole.authid'),
+				'pg_default_acl' => array('defaclrole.authid', 'defaclnamespace.namespace'),
+				'pg_depend' => array('classid.class', 'refclassid.class'),
+				'pg_description' => array('classoid.class'),
+				'pg_enum' => array('enumtypid.type'),
+				'pg_event_trigger' => array('evtowner.authid', 'evtfoid.proc'),
+				'pg_extension' => array('extowner.authid', 'extnamespace.namespace', 'extconfig.class'),
+				'pg_foreign_data_wrapper' => array('fdwowner.authid', 'fdwhandler.proc', 'fdwvalidator.proc'),
+				'pg_foreign_server' => array('srvowner.authid', 'srvfdw.foreign_data_wrapper'),
+				'pg_foreign_table' => array('ftrelid.class', 'ftserver.foreign_server'),
+				'pg_index' => array('indexrelid.class', 'indrelid.class', 'indkey.attribute.attnum', 'indcollation.collation', 'indclass.opclass'),
+				'pg_inherits' => array('inhrelid.class', 'inhparent.class'),
+				'pg_init_privs' => array('classoid.class'),
+				'pg_language' => array('lanowner.authid', 'lanplcallfoid.proc', 'laninline.proc', 'lanvalidator.proc'),
+				'pg_largeobject' => array('loid.largeobject_metadata'),
+				'pg_largeobject_metadata' => array('lomowner.authid'),
+				'pg_namespace' => array('nspowner.authid'),
+				'pg_opclass' => array('opcmethod.am', 'opcnamespace.namespace', 'opcowner.authid', 'opcfamily.opfamily', 'opcintype.type', 'opckeytype.type'),
+				'pg_operator' => array('oprnamespace.namespace', 'oprowner.authid', 'oprleft.type', 'oprright.type', 'oprresult.type', 'oprcom.operator', 'oprnegate.operator', 'oprcode.proc', 'oprrest.proc', 'oprjoin.proc'),
+				'pg_opfamily' => array('opfmethod.am', 'opfnamespace.namespace', 'opfowner.authid'),
+				'pg_partitioned_table' => array('partrelid.class', 'partdefid.class', 'partattrs.attribute.attnum', 'partclass.opclass', 'partcollation.collation'),
+				'pg_policy' => array('polrelid.class', 'polroles.authid'),
+				'pg_proc' => array('pronamespace.namespace', 'proowner.authid', 'prolang.language', 'provariadic.type', 'prosupport.proc', 'prorettype.type', 'proargtypes.type', 'proallargtypes.type', 'protrftypes.type'),
+				'pg_publication' => array('pubowner.authid'),
+				'pg_publication_namespace' => array('pnpubid.publication', 'pnnspid.namespace'),
+				'pg_publication_rel' => array('prpubid.publication', 'prrelid.class', 'prattrs.attribute.attnum'),
+				'pg_range' => array('rngtypid.type', 'rngsubtype.type', 'rngmultitypid.type', 'rngcollation.collation', 'rngsubopc.opclass', 'rngcanonical.proc', 'rngsubdiff.proc'),
+				'pg_rewrite' => array('ev_class.class'),
+				'pg_seclabel' => array('classoid.class'),
+				'pg_sequence' => array('seqrelid.class', 'seqtypid.type'),
+				'pg_shdepend' => array('dbid.database', 'classid.class', 'refclassid.class'),
+				'pg_shdescription' => array('classoid.class'),
+				'pg_shseclabel' => array('classoid.class'),
+				'pg_statistic' => array('starelid.class', 'staattnum.attribute.attnum', 'staop.operator', 'stacoll.collation'),
+				'pg_statistic_ext' => array('stxrelid.class', 'stxnamespace.namespace', 'stxowner.authid', 'stxkeys.attribute.attnum'),
+				'pg_statistic_ext_data' => array('stxoid.statistic_ext'),
+				'pg_subscription' => array('subdbid.database', 'subowner.authid'),
+				'pg_subscription_rel' => array('srsubid.subscription', 'srrelid.class'),
+				'pg_tablespace' => array('spcowner.authid'),
+				'pg_transform' => array('trftype.type', 'trflang.language', 'trffromsql.proc', 'trftosql.proc'),
+				'pg_trigger' => array('tgrelid.class', 'tgparentid.trigger', 'tgfoid.proc', 'tgconstrrelid.class', 'tgconstrindid.class', 'tgconstraint.constraint', 'tgattr.attribute.attnum'),
+				'pg_ts_config' => array('cfgnamespace.namespace', 'cfgowner.authid', 'cfgparser.ts_parser'),
+				'pg_ts_config_map' => array('mapcfg.ts_config', 'mapdict.ts_dict'),
+				'pg_ts_dict' => array('dictnamespace.namespace', 'dictowner.authid', 'dicttemplate.ts_template'),
+				'pg_ts_parser' => array('prsnamespace.namespace', 'prsstart.proc', 'prstoken.proc', 'prsend.proc', 'prsheadline.proc', 'prslextype.proc'),
+				'pg_ts_template' => array('tmplnamespace.namespace', 'tmplinit.proc', 'tmpllexize.proc'),
+				'pg_type' => array('typnamespace.namespace', 'typowner.authid', 'typrelid.class', 'typsubscript.proc', 'typelem.type', 'typarray.type', 'typinput.proc', 'typoutput.proc', 'typreceive.proc', 'typsend.proc', 'typmodin.proc', 'typmodout.proc', 'typanalyze.proc', 'typbasetype.type', 'typcollation.collation'),
+				'pg_user_mapping' => array('umuser.authid', 'umserver.foreign_server'),
+			);
+			$return = array();
+			foreach ((array) $mapping[$table] as $val) {
+				list($source, $target, $column) = explode(".", "$val.oid");
+				$return[] = array("table" => "pg_$target", "source" => array($source), "target" => array($column));
+			}
+			return $return;
 		}
 	}
 
+	private function lowerCase($value) {
+		return (is_array($value) ? array_map(array($this, 'lowerCase'), $value) : strtolower($value));
+	}
+
 	private function schemata($catalog, $schema = null) {
 		return array("table" => "SCHEMATA", "source" => array($catalog . "_CATALOG", ($schema ?: $catalog) . "_SCHEMA"), "target" => array("CATALOG_NAME", "SCHEMA_NAME"));
 	}