Module, Block or?

Question

We are building a Drupal site to replace an old ASP.Net site.

This site will show a user's view of the information we have on/by/for them, their correspondence, the grades for the courses they have taken, the list of dues that they have paid, etc.

The information we want to show is all on an Oracle DB inside our firewall. We have a web service that exposes that information to us and currently use it in a ASP.Net application that we will be replacing.

We really won't be editing the content in the Admin interface at all, all the content will be generated from calls to the web service.

Would we write a module or a block or both to show this information to the user?

We're kind of new to Drupal and not really understanding the terminology.

Answer 1

A module is a "piece of functionality" which can extend Drupal's capabilities with a lot of different things - like a plugin/extension in another system. It might or might not add functionality which is visible on the frontend - there are pure API modules for example.

Blocks are pieces of specialized displays - like widgets. Many times what you can see in the sidebar of a page is nothing else but blocks. For example setting up a category list or a tagcloud in a blog could be (and perhaps should be) done via blocks.

Modules and blocks are related in some way: a module can provide different blocks to use, for example the core comments module provides the "Recent comments" block.

If you would like to understand the complete terminology, check out Pro Drupal 7 Development - it's a great start for developing for Drupal.

Answer 2

Drupal has an API called 'entities.' Entities define the relationship between Drupal content and a database and its storage. The major content types in Drupal 7 are implemented with the Entity API; node, user, taxonomy... All are entities. You can also implement your own entity types.

So, for instance, an external database could be defined in the site's settings.php file, named something like 'our_oracle_database.' Then you could define an entity by implementing hook_entity_info() in a module. This entity would show the table schema to Drupal, and Drupal would then be able to use that table as content. You'd then define a controller class for your entity, which would use your database for CRUD functions.

It's completely non-trivial, and not a thing to shoot off in one single answer on Drupal Answers.