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Are Oracle’s OWB tutorials for 11g worthwhile?

The answer is a definite “yes”! If you’re new to Oracle Warehouse Builder then these tutorials are an excellent place to start (you’ll find them here ).

What’s in them?

Oracle offers a set of twelve tutorials for OWB 11g. The tutorials, consisting of over 400 screens worth of material, cover most aspects of OWB. The first six tutorials cover the basics: importing metadata, designing static and dynamic data warehouse objects, deploying the objects to a target data warehouse schema, and executing the dynamic objects (mappings and process flows). The final six tutorials repeat some of the material covered in the first six, but, in addition, they cover some of the more niche tasks, such as data profiling, data deduplication, and the construction of experts (customized wizards).

The “How” of OWB

In general, one of the most frustrating aspects of working through a tutorial is that it is often difficult to relate the instructions in the tutorial to what you actually see on the screen. Not so with these tutorials. Replete with hundreds of screen dumps, each step in a tutorial is illustrated on a “click-by-click” basis. It’s very rare indeed to find yourself wondering what to do next.

The “Why” of OWB

While the tutorials are very good at illustrating the “how” of OWB, they are less satisfactory when it comes to illustrating the “why”. While a little conceptual background is provided with some of the tutorials, it’s not uncommon for newbie OWB developers to end up slightly “shell-shocked”, “Wow! That tutorial was easy to follow, but I’m not quite sure exactly what it was that I did!”:

One reason for this lack of understanding is intrinsic to the design of OWB. Unlike developing in more familiar environments, such as SQL, PL/SQL, or SQL*Loader, OWB deliberately abstracts the development process. This process of abstraction ultimately has advantages when it comes to developing and managing large data warehouse projects, but it does add to the initial learning curve;

Another reason for a lack of understanding is that the tutorials make extensive use of wizards that often perform several tasks at the same time, which makes it more difficult to understand the fundamental building blocks from which OWB projects are constructed; and

Then there’s the issue of the level of understanding of data warehousing – or rather the lack of it – that you may bring to these tutorials. If you’re not familiar with basic data warehousing concepts, like ETL, cubes, and dimensions, then trying to pick up these concepts at the same time as learning how they are implemented in OWB will be challenging.

How long does it take?

Oracle provides estimates of the time it should take you to complete each tutorial. These times are very, very optimistic! True, you can click your way through a tutorial in the recommended time, but if you hope to take away some understanding of what you’ve done, then you’ll probably need to double that time, particularly if you’re unfamiliar with data warehousing concepts.

What I’ve found to work well with developers new to OWB is to go through a tutorial in two passes: the first to make sure you can navigate your way through the tutorial and around the OWB interface; and the second to try to pick up the key concepts, to understand how they are implemented, and to appreciate how they can be combined in different ways to achieve the desired objective.

If you’ve time, you’ll find it helpful to work through the tutorial on the second pass using your own data and naming conventions, so that you can adapt the tutorial content to the actual design requirements that you’ll encounter when you come to use OWB in “anger”.

Screen snapshots – now you see them, now you don’t!

Because each tutorial contains so many screen snapshots, the download time for a tutorial can be considerable if you only have access to a slow Internet link. Oracle has taken this into account in designing the tutorials, and has ensured that only the text of a tutorial is downloaded and displayed by default. To display the screen snapshots, individually or collectively, you’ll need to click on one or more links.

What Oracle hasn’t considered, however, is that you may want to save the tutorial to disk and work through it at your convenience, and perhaps revisit it later by way of clarification. Unfortunately, when you try to save a web page to disk you’re likely to find that only the text – but not the screen snapshots – gets saved. So you might want to develop a workaround for this “feature” before you start the tutorials. One solution that works well is to use the HTML convert facility within Adobe Acrobat. Acrobat will add a “convert” icon to your browser when it’s installed. By clicking on the icon you can then save an entire web page – including its screen snapshots – to an Adobe “pdf” file.

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