Question

I don’t understand what’s the difference between those patterns Martin Fowler says :

Transaction Script organizes business logic by procedures where each procedure handles a single request from the presentation.

and

Table Module a single instance that handles the business logic for all rows in a database table or view.

Also

You can organize your Transaction Scripts into classes in two ways. The most common is to have several Transaction Scripts in a single class, where each class defines a subject area of related Transaction Scripts. This is straightforward and the best bet for most cases. The other way is to have each Transaction Script in its own class (Figure 9.1), using the Command pattern [Gang of Four].

So I can do that in Table Module I can have method for each presentation request, aslo I can use DataSet or RecordSet in Transaction Script pattern. Well how should I know which pattern should I use in my domain logic?

Answer 1

I believe that the basic difference is the scope of the business logic that is covered. In the Table Module, you are limited to a single table or view, but the Transaction Script is not.

For example, assume that you have a table keeping track of financial transactions and your business logic dictates that every time a financial transaction is updated, the budget related to the transaction is also updated in a separate table.

In the case of a Table Module, you would need two procedures, one for the financial transaction and one for the budget.

For Transaction Script, you would only need one that updates both tables.