Used versions:
Joomla 3.1.1, Postgresql 9.2.4, openSUSE 12.3

Trying to create an article being logged in but not as Administrator results in the following
errors in the database log:

 2013-05-26 12:25:57 CEST joomla joomla LOG:  statement: INSERT INTO "hp_content"
        ("title","alias","introtext","fulltext","catid","created","created_by","created_by_alias
","version","metakey","metadesc","access","metadata","language") VALUES 
        ('Test','test','Test Text','',82,'2013-05-26 10:25:57',1,'',1,'','',1,'{"tags":null}','*')
        RETURNING id
2013-05-26 12:25:57 CEST joomla joomla ERROR:  null value in column "images" violates not-null constraint
2013-05-26 12:25:57 CEST joomla joomla DETAIL:  Failing row contains (82, 0, Test, test, Test  Text, , 0, 82, 2013-05-26 10:25:57, 1, , 1970-01-01 00:00:00, 0, 0, 1970-01-01 00:00:00, 1970-01-01 00:00:00, 1970-01-01 00:00:00, null, null, null, 1, 0, , , 1, 0, {"tags":null}, 0, *, ).

After reading some posts it seems that MySQL has a default value "empty string" if no default is set.
To get the same behaviour in Postgresql I added default values to 3 columns of table "hp_content":

• images
• urls
• attribs

via

alter  table hp_content alter column  set default '';

I propose a patch to the installation script, which I haven't tested, but it should fix it.

Kind regards
Ethikrates

--- installation/sql/postgresql/joomla.sql  2013-04-27 00:39:21.000000000 +0200
+++ installation/sql/postgresql/joomla.sql.patch    2013-05-26 16:43:06.986555341 +0200
@@ -341,9 +341,9 @@
   "checked_out_time" timestamp without time zone DEFAULT '1970-01-01 00:00:00' NOT NULL,
   "publish_up" timestamp without time zone DEFAULT '1970-01-01 00:00:00' NOT NULL,
   "publish_down" timestamp without time zone DEFAULT '1970-01-01 00:00:00' NOT NULL,
-  "images" text NOT NULL,
-  "urls" text NOT NULL,
-  "attribs" character varying(5120) NOT NULL,
+  "images" text DEFAULT '' NOT NULL,
+  "urls" text DEFAULT '' NOT NULL,
+  "attribs" character varying(5120) DEFAULT '' NOT NULL,
   "version" bigint DEFAULT 1 NOT NULL,
   "ordering" bigint DEFAULT 0 NOT NULL,
   "metakey" text NOT NULL,