[GENERAL] best place to enfore rules

[Rick Schumeyer]

I’m new both to databases and postgres, so forgive me if this is a stupid question.   Where do people usually enforce business rules?  In the client application or in the database?   For example, I might have a rule “don’t allow customers to enter an order if their account is delinquent.”  I could create rules, triggers, etc. to prevent an entry into the “order” table given some condition in the “account” table.  Or I could put the logic on the client side.   I would think it would be better to do this inside the database.  I’m not familiar with how the client would know what is happening.  I guess the client can tell if an SQL command failed, but will the client know why it failed?