Set primary key to zero, since there isn't a good way to retrieve it.  Bug report: 5172
diff --git a/system/database/drivers/postgre/postgre_result.php b/system/database/drivers/postgre/postgre_result.php
index 2e1e003..78b9a60 100644
--- a/system/database/drivers/postgre/postgre_result.php
+++ b/system/database/drivers/postgre/postgre_result.php
@@ -90,7 +90,7 @@
 			$F->name 		= pg_field_name($this->result_id, $i);

 			$F->type 		= pg_field_type($this->result_id, $i);

 			$F->max_length	= pg_field_size($this->result_id, $i);

-			$F->primary_key = $i == 0;

+			$F->primary_key = 0;

 			$F->default		= '';

 

 			$retval[] = $F;