PEAA.4 – Web Presentation

Back when this book was written, using the web for building enterprise applications was a new practise.

Although, in the beginning, it was a common practise to mix presentation logic with business logic and even persistence logic (think HTML mixed with SQL), it soon became clear that it was very difficult to change the UI if it was not decoupled from all other logic.

The MVC patter, which was around since the late 1970s, came to the resqueue and became the common practise. The most important reason to use MVC is to decouple presentation logic from business logic.

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PEAA.3 – Mapping to relational DBs

There are 3 patterns to handle data persistence to relational DBs:

Active Record
Gateway
Data Mapper

Associated to this patterns, we have a few more design patterns to help implement the previous ones:

Unit of work
Identity map
Lazy loading

And we also have 3 patterns to structure the data in the DB:

Single table inheritance
Concrete table inheritance
Class table inheritance

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Software Architecture vs. Code – by Simon Brown

Simon Brown talks to us about how, now days, we have many diagramming tools and concepts which some of us like to use, and sometimes are even imposed upon the developers by the corporations managers, who actually have no idea of technicalities and the usefulness or not of those diagrams. However, despite the tools and concepts we have, when we create a diagram of the architecture of a software program we are developing, most of the time it ends up not matching the actual code, we can not see the architecture in the code.

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