now PostgreSQL seems to work...

servers/slapd/back-sql/rdbms_depend/pgsql/testdb_metadata.sql

@@ -70,6 +70,8 @@ insert into ldap_entries (id,dn,oc_map_id,parent,keyval) values (6,'documentTitl
 --	oc_name		the name of the objectClass; it MUST match the name of an objectClass that is loaded in slapd's schema
 insert into ldap_entry_objclasses (entry_id,oc_name) values (4,'referral');
 
+insert into ldap_entry_objclasses (entry_id,oc_name) values (2,'posixAccount');
+
 -- referrals mapping: entries that should be treated as referrals are stored here
 --	entry_id	the "ldap_entries.id" of the entry that should be treated as a referral
 --	url		the URI of the referral

tests/data/slapd-sql.conf

@@ -51,11 +51,11 @@ dbname          example
 dbuser          manager
 dbpasswd        secret
 
-#insentry_query  "insert into ldap_entries (id,dn,oc_map_id,parent,keyval) values ((select max(id)+1 from ldap_entries),?,?,?,?)"
 #
 # rdbms specific directives
 #
 # PostgreSQL
+#postgres#insentry_query  "insert into ldap_entries (id,dn,oc_map_id,parent,keyval) values ((select max(id)+1 from ldap_entries),?,?,?,?)"
 #postgres#upper_func      "upper"
 #postgres#strcast_func    "text"
 #postgres#concat_pattern  "?||?"

tests/scripts/test031-sql

@@ -223,7 +223,7 @@ case ${RDBMS} in
 	# list here the RDBMSes whose mapping allows writes
 	postgres)
 		MANAGERDN="cn=Manager,${BASEDN}"
-		$LDAPMODIFY -v -D "$MANAGERDN" -w $PASSWD \
+		$LDAPMODIFY -v -c -D "$MANAGERDN" -w $PASSWD \
 			-h $LOCALHOST -p $PORT1 > \
 			$TESTOUT 2>&1 << EOMODS
 version: 1