Is it better to use NOT NULL everywhere?

Question

Database

Do I understand correctly that it is best to use NOT NULL wherever possible? I understand that NULL is sometimes necessary (for example, when we add a product to the site, but we don’t know the price yet - this field can be made NULL), but if you look at the whole picture, what is the best thing to do?

Answer 1

It is better to do what the business logic requires. If there can be no price, obviously it should be NULL. Because 0 and NULL are completely different values: "free" and "no price", which means that in the first case the goods are sold for free, and in the second case they may not be sold.