More than one John Doe
Which is the right Customer?
Recall by the key
There is a lot of data out there, but how do you sift through it all to find what you’re looking for? That’s where keys come in. Keys allow us to efficiently retrieve data, as well as navigate from one physical table to another. This chapter defines keys and distinguishes between the terms candidate, primary, and alternate keys. Surrogate keys and foreign keys and their importance are also explained. Examples of how to leverage keys in CA ERwin Data Modeler are included.
Data elements identify, describe, or measure the entity instances in which they reside. There is often a need to find specific entity instances using one or more data elements. Those ...