Question

In my program, I need to make an organization chart starting with individuals and grouping them under a manager, then group those managers under senior managers etc… How do I do this with regards to the database?? This is a many to one relationship – which I thought was illegal and impossible – and would be like starting with the child table – individuals – before creating its parent – manager.
If someone can help point me in the right direction to design my database I’d really appreciate it!!

—-EDIT—-
Here’s a more detailed explanation of my problem:

Let’s say a user of my program starts by entering in 35 individuals they’d like to use on some project they’re going to work on. Now, there are several possible management positions that can be created and have employees/other (lower) managers assigned to those. The user doesn’t HAVE TO create any particular position, but can pick and choose and assign however they like. The only constraints are there will always be a top manager – let’s call him the President – and that he SHOULD (but doesn’t HAVE TO) only assign 5-10 people to any given manager (president included). So in this example we are starting with 35 individuals and a President. Now we start grouping the 35 individuals into teams and assigning one of them as manager. Say the user decides to have two teams of 6, two teams of 9, and one team of 5 – each of these groups has one of its individual members assigned as manager of that team. So now we have 5 teams, each under its own manager, and those five managers would now be assigned to the President. The program would let this go but warn the user that the number of individuals under a manager in the last team is less than 5 (is only 4). So the user can now (or at ANYtime) go back and change the organization. So let’s say he wants to fix this issue and changes up the teams. So he breaks up one of the two teams of 9 and assigns one individual to the team that was short a person. This makes a final count of 3 teams of 6 (5 individual members and one manager), one team of 9 (8 ind and 1 mngr), and one team of 8 (7 ind and 1 mngr) and all 5 team managers are assigned to the president.

Only in real life this can get broken down much further – nests with many more levels of management. How can I do this?

Is Joe Hopfgartner’s answer below still valid? Can I just make a “role” column, even though the role would be assigned later (after the row is initially created)? Or changed at any time? Can this self-referencing foreign key be null? (as it would be in the case that no manager has been assigned yet) Or should I move the individuals to a separate “team” table after they’ve been assigned to a team and move the managers to a “manager” table once they’ve been assigned as a manager, then add a foreign key for the team table referencing the manager table?

Also, I am using MySQL, so does that fact that you cannot use self-referential ON UPDATE CASCADE or ON UPDATE SET NULL operations affect my particular case (since users will no doubt often be changing the assignments)?

Thank you so much for helping me with this!!!

Answer 1

if one individual can only have one manager, just introduce a “parent person” id field or put managers in a seperate table.

if not, create another table for a relation like “person_has_manager” that assigns a person to a manager.

you can also put managers and persons into the same table and introduce a “role” field, but this can be tricky when using foreign key constraints if you want to ensure that only manages can have persons assigned to them.

to solve this problem you can introduce a “person_is_manager” table that links person to their job as manager, and persons can be linked to be managed by that manager. this ould look like this:

persons
-> person_id (primary)
-> name
-> etc

managers
-> person_id (primary, linked to person_id in persons)

person_has_manager
-> person_id (primary)
-> manager_id (primary, linked to person_id in managers table)