If there is a repeating field, then the database is going to be unnormalised and thus contain redundant data. This is not a good idea for any database implementation.
If there is a repeating field, then the database is going to be unnormalised and thus contain redundant data. This is not a good idea for any database implementation.
Secondary keys were common in database systems of yester-year. These days the idea of secondary keys is not one which is used.
As a student can attend multiple events, and each event may involve multiple students, then the relationship must be many to many. This cannot be implemented in a relational database, and must be implemented using one to many and many to one relationships and an intermediate relation which contains the keys of the event/student combination as foreign keys.
There is a good correct answer available above. The question is really asking about how students relate to events. As a student can attend multiple events, and each event may involve multiple students, then the relationship must be many to many. How can this best be implemented in a relational database?
A timetable database is required for a University Department. Each taught event is part of a module, each event will have exactly one member of staff associated and several individual students. Each event takes place in a single weekly time slot. Each time slot has a day of the week and a time of day associated.
Which of the following is the best approach to implementing the attends relation using a relational database system?- A repeating field attends is included as part of the event table
- A repeating field attends is included as part of the student table
- A secondary attends key is added to the event table
- A table attends contains an event/student pair for every instance of a student attending an event
- None of the above
| ||||
| ||||
|