Loading all the tables and columns from a oracle db

get_tables_and_columns.plsql

BEGIN 
    dbms_output.Put_line (USER 
                          || ' Tables in the database:'); 

    FOR t IN (SELECT table_name 
              FROM   user_tables) LOOP 
        dbms_output.Put_line(t.table_name); 

        FOR i IN (SELECT column_name 
                  FROM   user_tab_cols 
                  WHERE  table_name = t.table_name) LOOP 
            dbms_output.Put_line(i.column_name); 
        END LOOP; 
    END LOOP; 
END;