Add a field - Date of completion with Date type to the registration table.Ensure Date of completion is greater that DOJ.

Question

What is the query for this, I tried altering the table and adding a constraint but it is not working.

Answer 1

You need to alter table, and use check contraint.
Tutorial links:
https://www.oracletutorial.com/oracle-basics/oracle-alter-table-add-column/
https://www.oracletutorial.com/oracle-basics/oracle-check-constraint/

If it doesn't help, post what you have tried so far.