i want to make continous numbering after deleting row
Tom Kyte, Oracle ACE and noted author, said it best over 12 years ago:
SEQUENCES WILL NEVER GENERATE A GAP FREE SEQUENCE OF NUMBERS!
See this AskTom is from 2001. It is just as valid now as it was then
Sequences will never generate a gap free sequence of numbers.
If someone calls seq.nextval and doesn't insert the value somewhere (or does insert it
and later rolls back their transaction) that number is GONE.
Sequences are database objects and may be aged out of the shared pool like everything
else -- it doesn't take a database shutdown to produce a gap.
You should never count on a sequence generating anything even close to a gap free
sequence of numbers.