In our previous blog post, we reviewed what a customer relationship management (CRM) system is and put together the requirements for a basic CRM. Yet, we’re not quite ready to start writing code. Next, we need to draw up an entity relationship diagram - ERD for short. In database land, this is a map of all the buckets of information that we will track and the connected data among them. As part of this process, we will look for places to normalize the data. Normalizing means we will look for instances where we can avoid entering the same data in two different areas.