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GEFP Model Design

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cysun Posts: 2935	Posted 10:53 Feb 02, 2015 \| When it comes to model design, some decisions are routine or obvious, e.g. each entity class should have a `id` field and `User` should have `username` and `password`, but some need more thinking. For GEFP, I think the answers to the following questions are important: How to model a flight plan? How to handle plan changes and how these changes are reflected in the students' view? How to store student data (i.e. the checkpoints each student checked)? How to model different types of users? Attached is a sketch of my design that answers these questions. We'll discuss this and HW3 in general in class. Attachments: Cell.java Checkpoint.java Department.java Plan.java Runway.java Stage.java User.java Last edited by cysun at 11:23 Feb 02, 2015.
cysun Posts: 2935	Posted 15:22 Feb 03, 2015 \| Here's a post I wrote a few years ago about naming conventions, and here's a copy of Coding Conventions for Java.
lmann2 Posts: 156	Posted 20:34 Feb 09, 2015 \| Why doesn't the model for Plan.java have a Department field? The relationship should be one to one, right?
cysun Posts: 2935	Posted 21:14 Feb 09, 2015 \| lmann2 wrote: Why doesn't the model for Plan.java have a Department field? The relationship should be one to one, right? There are two relationships between Department and Plan - one is one-to-one and the other is one-to-many. I agree that it's better to have a Department field in Plan, which creates a bidirectional association for the one-to-many relationship (not the one-to-one relationship).
lishenyu Posts: 103	Posted 10:36 Feb 11, 2015 \| Hi professor , I am facing a problem, eg I want to add a plan to a department ,while in the addPlan jsp , the modelAttribute is a plan object which has no departmentId field .(I didn't put a department id field in Plan because in Department it has a planId field) , so after I add a plan and click submit in addPlan jsp ,it will tell an error because I department_id is missing . So that's : departments.html?id=1 --->addPlan.html -->departments.html . So could you give me some ideas how to pass an id in this situation ?Thank you !
cysun Posts: 2935	Posted 12:48 Feb 11, 2015 \| lishenyu wrote: Hi professor , I am facing a problem, eg I want to add a plan to a department ,while in the addPlan jsp , the modelAttribute is a plan object which has no departmentId field .(I didn't put a department id field in Plan because in Department it has a planId field) , so after I add a plan and click submit in addPlan jsp ,it will tell an error because I department_id is missing . So that's : departments.html?id=1 --->addPlan.html -->departments.html . So could you give me some ideas how to pass an id in this situation ?Thank you ! You should have a department field in Plan. Read and understand my post above.
lishenyu Posts: 103	Posted 12:56 Feb 11, 2015 \| as you have said it's not common to have a circular in db , if in department there is plan_id , and in plan there is department_id , so when drop the tables there will be errors because they are dependent on each other ?
cysun Posts: 2935	Posted 12:58 Feb 11, 2015 \| lishenyu wrote: as you have said it's not common to have a circular in db , if in department there is plan_id , and in plan there is department_id , so when drop the tables there will be errors because they are dependent on each other ? I said it's not uncommon to have circular foreign key references, and I also explained how to drop the tables.