The Integration and Transformation Layer Component
The source of data for the ODS and the data warehouse is an architectural component known as the integration and transformation layer (the I & T layer), discussed briefly in Chapter 4. Unlike the ODS, data warehouse, and data marts, which are made up primarily of data, the I & T layer is made up primarily of programs. In the spirit of the metaphor of an actual factory, the I & T layer is where most of the factory work takes place. Figure 5.1 shows the I & T layer (or interface).
Figure 5.1 The I & T layer: a group of programs dedicated to the capture, transformation, and movement of data from the applications environment to the ODS and the data warehouse environment.
What Is the Integration and Transformation Layer?
The I & T interface is the place where unintegrated data from the applications is combined—or integrated—and transformed into corporate data. As we will see later in this chapter, significant transformations take place as data moves through the I & T layer. After this data has been molded into a corporate asset, the I & T layer loads it into the data warehouse and/or ODS for access by the user community.
An Unstable Interface
The I & T interface is a very unstable set of programs, because they constantly change over time for the following reasons (see Figure 5.2):
The applications are constantly changing. ...