Oracle check constraint null not null

Not Null constraints are also defined as check constraints and have search conditions as column name not null. We can give the custom name to the Not Null constraint also.

Here is the example to demonstrate it. If you try to add a not-null constraint on the column containing null values, then that command will fail as it will validate all the rows all the existing rows for not null constraint. Sometimes we want to keep the existing null values and check for future rows that they contain a not null value for this column, then, in that case, we may enable the constraint with novalidate clause.

With this clause, it will not check the existing rows, but future rows will be checked. Your email address will not be published. How are we doing? Please help us improve Stack Overflow. Take our short survey. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow.

Learn more. Oracle constraint check condition with null and not null Ask Question. Asked 8 years, 6 months ago. Active 4 years, 11 months ago. Viewed 10k times. Improve this question. Moudiz Moudiz 6, 19 19 gold badges 70 70 silver badges bronze badges. Show 1 more comment. Active Oldest Votes.

More on the foreign key. Improve this answer. APC What do you mean by :Use a foreign key to a lookup table instead? I have to specify what is the status and what is the color. Add a comment. Sign up or log in Sign up using Google.