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Primary keys - the basics
Single-column primary keys
Multicolumn primary keys
15. Uniqueness with multicolumn primary keys - continued
Auto-increment columns and sequences


Nice! We have successfully inserted the new row because the combination title + year was unique.

What happens if the combination of values is not unique? Let's find out.


Try to add a new movie where the combination title + year is the same as for another row. You can, for instance, try to add yet another movie The Kid produced in 2016.