as a programmer or dba which is using oracle as dbms backend, using sequence is pretty easy for generating sequence number which is similar as auto increment number on mysql.

but reseting this sequence number, is little tricky.
the easiest way to reset this sequence is alter the sequence syntax and use negative number as increment value to reduce the next value on that sequence. this negative number can be valued as we need.

this is the syntax :

alter sequence seq_name
increment by negative_value