SEQUENCE

SEQUENCE: A sequence is an object in oracle, which is used to generate a series of numbers. It can generate unique sequential numbers for using in a primary key column of a table.

 

CURRVAL and NEXTVAL are called pseudo columns. CURRVAL returns the current value of a sequence. NEXTVAL increments the sequence and then returns the next value. A sequence can be modified using ALTER statement.

 SQL> ALTER SEQUENCE SS MAXVALUE 99999;

 

SQL> DROP SEQUENCE SS;