Entity relationship diagram
The final step is to draw the ERD, just like we did in Chapter 2, Entity Analysis. The understanding of ERDs you acquired in the aforementioned chapter will serve you well in understanding the results of normalizing. The key part of this step is to recognize all foreign keys. Using entity analysis, you think entities have relationships. Recognizing foreign keys means you now know that there are relationships and that you can tell the database about them later when implementing the database. You can show all columns in an ERD, or just show the tables as rectangles with just the table name written in them.
The ERD of our project administration is now as can be seen in Figure 3.16:
Figure 3.16 – ERD project administration
In Figure 3.16, the colors indicate the foreign keys and the relationships they implement. The value of drawing the ERD is twofold:
- To get an overall picture
- To show the necessary details