Tagged Questions

0
votes
1answer
69 views

How to model/structure data that contains parent/child relationships for the same entity?

I think it is just my thinking that is off here. Suppose I have two entities: question and choice. A question can be a parent or child, or both (in relation to other questions). It seems that this ...
3
votes
2answers
106 views

Does this situation call for well specified associations, single table inheritance, or polymorphic association?

I'm building a web-app where users can keep track of who owes whom money. I have users and debts. Given a user I want to be able to find out all the debts to other users, and all the loans to other ...
2
votes
2answers
127 views

how to model this relationship ? in ERD

I have three entities : Technician Vehicle Repair The question is how to model this in ERD? Knowing that a technician can repair multiple cars, and the same car can be repaired by one and only one ...
3
votes
2answers
109 views

Best Way to Express Meta-Info on Missing Data?

I work in healthcare IT, reviewing data management processes of various observational studies. One problem I have repeatedly faced is the poorly encoded data, especially when some values are missing. ...
7
votes
5answers
2k views

Is there a tool that creates database design diagrams? [closed]

I'm looking for an application to create simple diagrams for database design. I'm not looking for anything that will help create the databases, just a simple tool for a design report. I have tried ...