diff --git a/scripts-available/CDB_ColumnNames.sql b/scripts-available/CDB_ColumnNames.sql
index ce74216..c35ba99 100644
--- a/scripts-available/CDB_ColumnNames.sql
+++ b/scripts-available/CDB_ColumnNames.sql
@@ -2,15 +2,13 @@
 CREATE OR REPLACE FUNCTION CDB_ColumnNames(REGCLASS)
 RETURNS SETOF information_schema.sql_identifier
 AS $$
-
-    SELECT c.column_name
-      FROM information_schema.columns c, pg_class _tn, pg_namespace _sn
-      WHERE table_name = _tn.relname
-        AND table_schema = _sn.nspname
-        AND _tn.oid = $1::oid
-        AND _sn.oid = _tn.relnamespace
-      ORDER BY ordinal_position;
-
+  SELECT
+    a.attname::information_schema.sql_identifier column_name
+    FROM pg_class c
+         LEFT JOIN pg_attribute a ON a.attrelid = c.oid
+    WHERE c.oid = $1::oid
+    AND a.attstattarget < 0 -- exclude system columns
+   ORDER BY a.attnum;
 $$ LANGUAGE SQL;
 
 -- This is to migrate from pre-0.2.0 version
diff --git a/scripts-available/CDB_ColumnType.sql b/scripts-available/CDB_ColumnType.sql
index 8ddc36b..19b8934 100644
--- a/scripts-available/CDB_ColumnType.sql
+++ b/scripts-available/CDB_ColumnType.sql
@@ -2,15 +2,13 @@
 CREATE OR REPLACE FUNCTION CDB_ColumnType(REGCLASS, TEXT)
 RETURNS information_schema.character_data
 AS $$
-
-    SELECT c.data_type
-      FROM information_schema.columns c, pg_class _tn, pg_namespace _sn
-      WHERE table_name = _tn.relname
-        AND table_schema = _sn.nspname
-        AND column_name = $2
-        AND _tn.oid = $1::oid
-        AND _sn.oid = _tn.relnamespace;
-         
+  SELECT
+    format_type(a.atttypid, NULL)::information_schema.character_data data_type
+  FROM pg_class c
+       LEFT JOIN pg_attribute a ON a.attrelid = c.oid
+  WHERE c.oid = $1::oid
+  AND a.attname = $2
+  AND a.attstattarget < 0; -- exclude system columns
 $$ LANGUAGE SQL;
 
 -- This is to migrate from pre-0.2.0 version
diff --git a/scripts-available/CDB_Overviews.sql b/scripts-available/CDB_Overviews.sql
index 699ca5c..0e692e7 100644
--- a/scripts-available/CDB_Overviews.sql
+++ b/scripts-available/CDB_Overviews.sql
@@ -520,15 +520,14 @@ CREATE OR REPLACE FUNCTION _cdb_unlimited_text_column(reloid REGCLASS, col_name
 RETURNS BOOLEAN
 AS $$
   SELECT EXISTS (
-    SELECT  *
-      FROM information_schema.columns c, pg_class _tn, pg_namespace _sn
-      WHERE table_name = _tn.relname
-        AND table_schema = _sn.nspname
-        AND c.column_name = col_name
-        AND _tn.oid = reloid
-        AND _sn.oid = _tn.relnamespace
-        AND character_maximum_length IS NULL
-        AND c.data_type IN ('text', 'character varying', 'character')
+    SELECT a.attname
+    FROM pg_class c
+         LEFT JOIN pg_attribute a ON a.attrelid = c.oid
+         LEFT JOIN pg_type t ON t.oid = a.atttypid
+    WHERE c.oid = reloid
+      AND a.attname = col_name
+      AND format_type(a.atttypid, NULL) IN ('text', 'character varying', 'character')
+      AND format_type(a.atttypid, NULL) = format_type(a.atttypid, a.atttypmod)
   );
 $$ LANGUAGE SQL STABLE;