fetch the contraint name from oracle table

SELECT * FROM USER_CONSTRAINTS WHERE table_name ='ACCOUNT_STATEMENT' and constraint_name like 'CHK%';

fetch the contraint name from oracle table

SELECT * FROM USER_CONSTRAINTS WHERE table_name ='ACCOUNT_STATEMENT' and constraint_name like 'CHK%';

converting a number to time stamp

select trunc(sysdate) + 84736/86400 from dual

examples of Cursor FOR Loop in oracle

e.g.
SET SERVEROUTPUT ON
BEGIN
   FOR trip_record IN (SELECT bt_id_pk, bt_duration
                      FROM business_trips) LOOP
      -- implicit open/fetch occurs
      IF trip_record.bt_duration = 1 THEN
        DBMS_OUTPUT_LINE ('trip Number ' || trip_record.bt_id_pk
                        || ' is a one day trip');
      END IF;
   END LOOP; -- implicit CLOSE occurs
END;
/

Rename column in oracle

ALTER TABLE ACCOUNT_STATUS RENAME COLUMN delete_address_flag TO delete_history_flag;