Oracle dynamically creates auto-increasing Sequences

1.Dynamically create auto-increment Sequences: Declare
V_ SQL varchar2 (1000 );
V_num number (20): = 1;
Begin
V_ SQL: = 'create sequence sqbs ';
Select max (sqb. id) + 1 into v_num from sqb;
If v_num is null then v_num: = 1;
V_ SQL: = v_ SQL | 'maxvalue 999999 start with' | v_num | 'crement by 1 nocache ';
End if;
Execute immediate v_ SQL;
End;
2 -- create Sequence
Create sequence t-- Use sequence
Select t. nextval from dual -- get the next Sequence Value
Select t. currval from dual -- get the current Sequence Value
Drop sequence g -- delete a sequence
Alter sequence ttt increment by-3 -- modify the sequence