I am developing a large application where the previous developer used Martin Fowlers Transaction Script pattern.
The requirements are becoming more complex and it is becoming a bit of a maintenance nightmare. Therefore I have started to use Fowlers Domain Model and Table Data Gateway in an attempt to separate concerns and reuse code. It is becoming a refactoring process.
My question is: is it bad practice to mix and match patterns? e.g. using Transaction Script and Domain Model in the same application or is this relatively common practice?