(P3.14) Suppose that you have the ERM shown in Figure Q3.14. DRIVER TRUCK drives During some time interval, a DRIVER can drive many TRUCKs and any TRUCK can be driven by many DRIVERs FIGURE Q3.14 The Crow's Foot ERD for Question 14 How would you convert this model into an ERM that displays only 1:M relationships? Make sure that you draw the revised ERM. Specifically convert this M.N relationship into two 1Mrelationships - look at figure 3.26 to see example for STUDENT and CLASS. Use Crow's foot diagram as illustrated in Figures 3.17, 3.19, and 3.21 for ERM diagram. Write the business rules that apply to the two 1:M relationships and draw the revised ERM diagram. |