Oracle: How can I generate primary key values for my table?

Question

I have created one table where I want to add combination of multiple column as primary key.

Can someone please help me to know how to do this?

Answer 1

Create your table with a NOT NULL column (say SEQNO). This column can now be populated
with unique values:
SQL> UPDATE table_name SET seqno = ROWNUM;

or use a sequences generator:

SQL> CREATE SEQUENCE sequence_name START WITH 1 INCREMENT BY 1;
SQL> UPDATE table_name SET seqno = sequence_name.NEXTVAL;

Finally, create a unique index on this column.