Try to cast TEXT typed updated_at and created_at if present

If the cast fails we'll still rename those fields and create
new ones. See #27 (cartodb_id is still not done)

scripts-available/CDB_CartodbfyTable.sql

@@ -163,27 +163,26 @@ BEGIN
 
       IF had_column THEN
 
-        -- Check data type is a TIMESTAMP WITH TIMEZONE
-        SELECT t.typname, t.oid, a.attnotnull FROM pg_type t, pg_attribute a
-         WHERE a.atttypid = t.oid AND a.attrelid = reloid AND NOT a.attisdropped
-           AND a.attname = rec.cname
-        INTO STRICT rec2;
-        IF rec2.oid NOT IN (1184) THEN -- timestamptz {
-          RAISE NOTICE 'Existing % field is of invalid type % (need timestamptz), renaming', rec.cname, rec2.typname;
-        ELSE -- }{
-          sql := 'ALTER TABLE ' || reloid::text || ' ALTER ' || rec.cname
-            || ' SET NOT NULL, ALTER ' || rec.cname || ' SET DEFAULT now()';
+        -- Ensure data type is a TIMESTAMP WITH TIMEZONE
+        sql := 'ALTER TABLE ' || reloid::text
+          || ' ALTER ' || rec.cname
+          || ' SET NOT NULL,'
+          || ' ALTER ' || rec.cname
+          || ' TYPE timestamptz USING ' || rec.cname || '::timestamptz,'
+          || ' ALTER ' || rec.cname
+          || ' SET DEFAULT now()';
         BEGIN
           RAISE DEBUG 'Running %', sql;
           EXECUTE sql;
           EXIT column_setup;
         EXCEPTION
-          WHEN not_null_violation THEN
+        WHEN not_null_violation THEN -- failed not-null
+          RAISE NOTICE '%, renaming', SQLERRM;
+        WHEN cannot_coerce THEN -- failed cast
           RAISE NOTICE '%, renaming', SQLERRM;
         WHEN others THEN
           RAISE EXCEPTION 'Got % (%)', SQLERRM, SQLSTATE;
         END;
-        END IF; -- }
 
         -- invalid column, need rename and re-create it
         i := 0;

test/CDB_CartodbfyTableTest.sql

@@ -170,6 +170,14 @@ SELECT CDB_CartodbfyTableCheck('t', 'trigger-protected the_geom');
 SELECT 'extent',ST_Extent(ST_SnapToGrid(the_geom,0.1)) FROM t;
 DROP TABLE t;
 
+-- table with existing updated_at and created_at fields ot type text
+CREATE TABLE t AS SELECT NOW()::text as created_at,
+                         NOW()::text as updated_at,
+                         NOW() as reftime;
+SELECT CDB_CartodbfyTableCheck('t', 'text timestamps');
+SELECT reftime-created_at, reftime-updated_at FROM t;
+DROP TABLE t;
+
 -- TODO: table with existing custom-triggered the_geom
 
 DROP FUNCTION CDB_CartodbfyTableCheck(regclass, text);

test/CDB_CartodbfyTableTest_expect

@@ -25,5 +25,9 @@ CREATE TRIGGER
 trigger-protected the_geom cartodbfied fine
 extent|BOX(1 1,2 2)
 DROP TABLE
+SELECT 1
+text timestamps cartodbfied fine
+@ 0|@ 0
+DROP TABLE
 DROP FUNCTION
 DROP FUNCTION