CDA was one of the first CTools. Its main purpose is to provide data abstraction for multiple kinds of data sources wrapped as web services. It was first created to be used as an interface between the data connections and the Community Dashboard Framework (CDF), but nowadays it can also be used in Report Designer to embed data in third-party applications.

CDA includes many different output types that we can configure, and also includes some configurable cache options to optimize performance, which you will have the chance to learn about. Another great feature in CDA that is somehow related to performance, is to sort and paginate on the server side.

The following diagram is an example of how CDA can be used to acquire data from. CDA is able to provide data to a CDF and/or CDE dashboards. However, an external application can get data directly from CDA using its endpoints. When requested for data, CDA will check whether the cache is enabled and whether there are results...

There are multiple ways to create CDA data sources. One of the ways is to use CDE, where no code or XML is needed, and we will cover this later in the CDE chapter. There is another way, which is using the CDA editor, or just editing the file by hand using the Pentaho Text Editor plugin.

For now, I want you to understand the internals of CDA, so we need to start with the hardest way to create a CDA file—by creating/editing an XML file. The CDA files that are XML files will define the Pentaho repository and will have a .cda extension. This way, Pentaho will recognize the file extension and will provide the capability to preview the results or edit the file. The main structure of a CDA file is the following:

<?xml version="1.0" encoding="UTF-8"?>
<CDADescriptor>
   <DataSources>
      <!—- HERE LIVES EACH ONE OF <Connection>-->
   </DataSources>
   <!—- HERE LIVES EACH ONE OF <DataAccess> -->
</CDADescriptor&gt...

The data sources covered in this book are the ones already pointed out previously, but we need to see them in detail. To create a new data source, you should also specify the attribute type that will be used to distinguish the method to be called on the server side to get the data and return the results. Depending on the data source that you are creating, you should also specify some properties that may be different depending on the kind of data source. Let's look at each one of the available options.

Each one of the following distinguished subsections will give you a brief overview and inform you about the properties that should be defined for the connections and also for the Data Access types. There are some common properties, such as the columns, that we will cover later in this chapter. For now, we will only focus on the different ones.

There are some common properties that should or can be used when defining a Data Access. These properties are:

Once you have created a file and uploaded it to BA Server, the .cda extension will tell Pentaho how to handle this file. When clicking on a .cda file, in the context menu that becomes available on the right side of Pentaho User Console (PUC), you will be able to edit and open the previewer. When selecting edit, you will see a screen like the following:

You can see the editor on the center of the page, and three buttons on the right-hand side, above the editor. We are able to change the XML file and use the buttons to trigger some actions. The available actions are:

There are two ways to preview a query result when using CDA. The first one is using the CDA previewer, a GUI that will let you select the Data Access that you would like to execute. To open the previewer, you...