I have a relation between two tables. The foreign key table can have a row related in the primary table. There's a way to enforce the value of the FK column to be NULL or one of the values of the PK column in the primary table?
Database Administrators Stack Exchange is a question and answer site for database professionals who wish to improve their database skills and learn from others in the community. It's 100% free, no registration required.
Here's how it works:
- Anybody can ask a question
- Anybody can answer
- The best answers are voted up and rise to the top
Yes, why not? Did you try it?
If this is not what you meant, then please elaborate or re-word your question.