I am new to creating ER diagrams and was wondering if anyone could review one that I constructed for an assignment. I used min, max notation in my design but I am not entirely sure if I did everything correctly.


I would like to create a simple database that tracks my job history.

The database tracks my employee information: name, email, phone number, hire date (if known), and current salary. For each job it tracks the department I worked at, including the department name, manager and location.

In some cases I worked remotely, in those cases the database indicates that I did work remotely and lists the nearest office location. Each job has a title, starting salary and an ending salary.

Because I could have multiple positions at the same company the job history portion of the database is uniquely identified by my employee id and start date. The history portion also has my end date for a role.

Assume I can only work for one department at a time and that the database tracks only one job at a time. Also assume that I want to track the information of a few of my team mates (not their salaries of course).

A single employee can have multiple job histories. A single employee can have one or more jobs. Job histories are associated with a single department.

What other assumptions might you need to simplify this example? Remember submitted ER models should be in the standard or the (min, max) notations.

Draw an ER model that represents the above requirements description. What assumptions do you need to make, if any, to complete the diagram? If needed make assumptions to simplify the final ER. Bear in mind that not every app view or field discussed above is required to be represented on the ER diagram. Additionally, in some cases the requirements may list irrelevant details that do not need to be represented.

Here is the diagram I constructed.

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Any feedback would be greatly appreciated.

  • Dude... this is straight up homework hahaha
    – Nelson
    Commented Apr 12, 2020 at 23:13

1 Answer 1


1) There are 2 independent relations: from Employee to Job and from Employee to Job History. This means, that potentially Employee can have Jobs that are not contained in the Job History, and vice versa, there can be Job History elements for which there is no element in the Job relation.

2) Wording is misleading. Based on relation from Job to Job History one can suppose that StartDate and EndDate mean period where this Job existed. To different times different Employees could have been assigned to this Job. But based on the relation from Employee to Job History one can suppose that StartDate and EndDate means dates of assignment of particular employee to this Job. Which of these you mean is not clear.

3) I would expect that Job is related to Department, not the Job History.

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