Re: Transaction Oriented Architecture (TOA)

Responding to Gagne...

I was going to call it Transaction Oriented Processing, but didn't want its acronym confused with another, already more popular, in comp.object.

<http://blogs.in-streamco.com/anything.php?title=transaction_oriented_architecture_aka_th>

I would point out that your notion of 'transaction' is different than that of the typical RDBMS. The need for, content of, and timing of audit transactions is driven solely by the problem domain. OTOH, the notion of 'transaction' in the database is related to providing scope for data integrity _within the database_ when queries are processed. (Alas, 'transaction' is one of those terminally overloaded words in the computing space.)

One of the problems of synchronizing problem solutions to databases is providing mapping between such disparate notions, which segues to...

In the article I propose the impedance mismatch between Object Oriented Languages can Relational Databases can be easily eliminated. All we have to do (as OO programmers and designers) is stop pretending the database doesn't exist.

I don't think the issue is ignoring the database; it is recognizing that the database is a different subject matter applying different business rules than the problem solution. Enter stage left, dancing: separation of concerns and decoupling through subsystem encapsulation.

There is nothing to prevent abstracting the database subject matter in a classic OO manner with objects like Schema, Table, Tuple, and Query. One can provide behaviors to deal with database-specific mechanics like the construction of SQL strings. One can easily provide optimizations tailored to the database paradigm de jour. One just has to realize that problem one is solving in accessing a database is different than the problem the application is solving for the customer (at least outside the CRUD/USER arena).

It seems to me the article was most of the way there when it proposes things like isolating SQL so it is not embedded in the problem solution and emphasizing low coupling between modules. It just didn't say specifically that one needs to encapsulate database access in a subsystem behind an interface to do that. B-)


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Relevant Pages

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