Attendance Assistant ER Figure 2.0 version of the problem

, attendance Assistant ER Figure 2.0, the lack of a personal mailbox Although the problem does not have a logical level, but it is not satisfied with the requirements, that is, such a design can not meet the team's initial design of the attendance assistant. Secondly, on the design level to analyze, weak connection is the database query in the more taboo point, although logically feasible, but in the subsequent programming query related data, multi-table query access is very poor implementation, so the group decided to modify this after the consultation. Finally, the "Time table" of the disagreement, the other two members of the idea is to specify the class query designated class attendance, but I and the team leader's view is able to view the attendance of multiple classes, so the effect more intuitive. The above is the main problem found after the panel discussion, the leader will also make the relevant changes to generate Database version 3.0.

Attendance Assistant ER Figure 2.0 version of the problem