drop all tables and sequences in oracle
tables:
SELECT 'DROP TABLE ' || table_name || ' CASCADE CONSTRAINTS;' FROM user_tables;
sequences:
SELECT 'DROP SEQUENCE ' || sequence_name || ';' FROM user_sequences;
web, coding and beyond
tables:
SELECT 'DROP TABLE ' || table_name || ' CASCADE CONSTRAINTS;' FROM user_tables;
sequences:
SELECT 'DROP SEQUENCE ' || sequence_name || ';' FROM user_sequences;