[sonnyblarney]

"Applications generally can't recreate ACID properties" - why would they?

ACID and 'data validation' are generally separate issues.

Data generally has to be validated as it enters the business logic, before it gets stored in a DB. While a DB may in some cases ensure that data adheres to a schema, this usually does not fulfill all of the validation requirements.

[jacques_chester]

Validation often requires examine a model beyond "is this an int?". That model needs to be self-consistent. That requires atomic movements from consistent state to consistent state.

You can do that yourself. Or let the database do it. For things where you can't express it in a database schema, sure. But you'd be surprised how far it gets you.