Summary
In this chapter we have introduced the key building blocks of the ETL system. As you may now better appreciate, building an ETL system is unusually challenging; the ETL system must address a number of demanding requirements. This chapter identified and reviewed the 34 subsystems of ETL and gathered these subsystems into four key areas that represent the ETL process: extracting, cleaning and conforming, delivering, and managing. Careful consideration of all the elements of the ETL architecture is the key to success. You must understand the full breadth of requirements and then set an appropriate and effective architecture in place. ETL is more than simply extract, transform, and load; it’s a host of complex and important tasks. In the next chapter we will describe the processes and tasks for building the ETL system.