What Does Consistency Mean?
Consistency, in the context of databases, states that data cannot be written that would violate the database’s own rules for valid data. If a certain transaction occurs that attempts to introduce inconsistent data, the entire transaction is rolled back and an error returned to the user.
Techopedia Explains Consistency
Consistency rules are vitally important while creating databases, as they are the embodiment of the business rules for which the database is being created. They also serve another important function: they make the application developers’ work easier- it is usually much easier to define consistency rules at the database level rather than defining them in the application that connects to the database.