Let’s look at the two models in Figure 7.3.
Figure 7.3 Independent and Dependent entities
Customer and Account in the first example, and Customer in the second example are rectangles, yet Account in the second example is a rectangle with rounded corners, called a bub-tangle. The rectangles with straight right angle corners are independent and those with rounded corners are dependent.
An independent entity such as Customer in both examples and Account in the first example, is an entity where each occurrence (instance) can be found using only attributes that it owns, such as a Customer ID. A dependent entity such ...