So far, we have focused on creating datasets and using multiple functions. With a plethora of datasets, the one thing that you want to do at times is combine them. A typical database will have thousands of datasets. Some larger organizations already have millions of datasets. But why would we need to combine them? If you are working for the tax authorities, you might want to merge the information you hold on individuals with the current account information you may have received from various banks. We will explore various combining techniques in this chapter.
Combining large datasets requires a lot of computing resources and takes longer to complete. This is where indexing comes in handy. We have already looked at the compress function, but there is another compression technique for datasets that helps increase...