diff -ur drupal-6.11.dist/includes/database.pgsql.inc drupal-6.11/includes/database.pgsql.inc
--- drupal-6.11.dist/includes/database.pgsql.inc	2009-03-30 15:04:06.000000000 +0200
+++ drupal-6.11/includes/database.pgsql.inc	2009-05-08 20:37:17.000000000 +0200
@@ -281,6 +281,7 @@
   }
   _db_query_callback($args, TRUE);
   $query = preg_replace_callback(DB_QUERY_REGEXP, '_db_query_callback', $query);
+	$query = preg_replace('/\'\'/', '\'', $query );   // line added by np@bsn.com 20090430
   $query .= ' LIMIT '. (int)$count .' OFFSET '. (int)$from;
   return _db_query($query);
 }
@@ -505,9 +506,18 @@
   if (isset($table['primary key']) && is_array($table['primary key'])) {
     $sql_keys[] = 'PRIMARY KEY ('. implode(', ', $table['primary key']) .')';
   }
+
+  // np@bsn.com 20090430 added 5 lines:
+  if ( preg_match('/\.(.*$)/', $name , $matches )){
+    $constraintName = $matches[1];
+  } else {
+    $constraintName = $name;
+  }
+
+  // np@bsn.com 20090430 use $constraintName:
   if (isset($table['unique keys']) && is_array($table['unique keys'])) {
     foreach ($table['unique keys'] as $key_name => $key) {
-      $sql_keys[] = 'CONSTRAINT {'. $name .'}_'. $key_name .'_key UNIQUE ('. implode(', ', $key) .')';
+      $sql_keys[] = 'CONSTRAINT {'. $constraintName .'}_'. $key_name .'_key UNIQUE ('. implode(', ', $key) .')';
     }
   }
 
@@ -776,6 +786,11 @@
  *   The table to be altered.
  */
 function db_drop_primary_key(&$ret, $table) {
+  // np@bsn.com: enable sites/settings/prefix with trailing dot for postgreSQL schema usage:
+	if ( preg_match('/\.(.*$)/', $table , $matches )){
+		$table = $matches[1];
+	} 
+
   $ret[] = update_sql('ALTER TABLE {'. $table .'} DROP CONSTRAINT {'. $table .'}_pkey');
 }
 
@@ -792,7 +807,14 @@
  *   An array of field names.
  */
 function db_add_unique_key(&$ret, $table, $name, $fields) {
-  $name = '{'. $table .'}_'. $name .'_key';
+  // np@bsn.com changed for enabliing sites/settings/prefix with trailing dot for postgreSQL schema usage:
+  if ( preg_match('/\.(.*$)/', $table , $matches )){
+    $tableWithoutSchema = $matches[1];
+  } else {
+    $tableWithoutSchema = $table ;
+  }
+
+  $name = '{'. $tableWithoutSchema .'}_'. $name .'_key';
   $ret[] = update_sql('ALTER TABLE {'. $table .'} ADD CONSTRAINT '.
     $name .' UNIQUE ('. implode(',', $fields) .')');
 }
@@ -808,7 +830,14 @@
  *   The name of the key.
  */
 function db_drop_unique_key(&$ret, $table, $name) {
-  $name = '{'. $table .'}_'. $name .'_key';
+	// np@bsn.com: for postgreSQL schema
+  if ( preg_match('/\.(.*$)/', $table, $matches )){
+    $tableWithoutSchema = $matches[1];
+  } else {
+    $tableWithoutSchema = $table;
+  }
+
+  $name = '{'. $tableWithoutSchema .'}_'. $name .'_key';
   $ret[] = update_sql('ALTER TABLE {'. $table .'} DROP CONSTRAINT '. $name);
 }