Xcelerate provides some built-in asset (an absolute requirement to build a site). However, since WCS has a rich and flexible type system, you can define your own assets. Well, you actually should, unless you stick using sample assets, but you would lose a good deal of flexibility.
There is a lot to say about all the available possibilities to define your assets. For now, we limit the exploration to the features provided by Xcelerate, namely the Basic Assets. Actually, there is a more powerful and interesting possibility, Flex Assets, but this feature is part of Gator, that will be described later. Furthermore, Basic Assets are still useful although I do not recommend building a site (unless very simple and unlikely to evolve) solely on Basic Asset.
Let's jump start on Basic Asset showing an example how you can define it.
Although a bit technical as a approach (this is one of Basic Assets's drawback) you have to describe it creating an XML file.
A very simple example of a Basic Asset descriptor looks like this:
<ASSET NAME="Simple" DESCRIPTION="Simple" PROCESSOR="5.0"
DEFDIR="c:\Fatwire\Shared\Storage\Simple">
<PROPERTIES>
<PROPERTY NAME="value" DESCRIPTION="Value">
<STORAGE TYPE="VARCHAR" LENGTH="80"/>
<INPUTFORM TYPE="TEXT" WIDTH="50"
MAXLENGTH="80" REQUIRED="NO" DEFAULT="" MULTIPLE="NO"/>
</PROPERTY>
</PROPERTIES>
</ASSET>
It is a simple asset, maybe the simplest possible, but this example demonstrates what an Asset can provide.
First , as asset, like a database table, is essentially a sequence of fields, here called properties. As you can see here, each property has a storage type, so basically properties are translated in fields of a database table.
But you can also note an important difference from database table: for each field, it is declared how the field will be edited. In this example, you simply use a simple input text form, but with some constraints:
It is however also pretty simple declare a property of type blob, that will generate a form with a file upload. The file, once uploaded, will be stored in a folder. As you may remember we just discussed that tables may have attachments. Here we define the folder where attachments will be stored, and thus this information is mandatory.
Basically we have seen so far how an Asset extends the concept of database table providing informations for forms editing and attachments. Actually there is more, there are many pre-defined asset fields generating various for but we will investingate on those features later. For now, just understand the concept.
Please note that Basic Assets have however some limitation. Most notably:
In the following of this tutorial we will see how those limitations has been overcome by Flex Assets, at the price of increased complexity and lower performances (however compensated by the widespread use of caching in WCS).