Hi everyone,

I'm trying to convince my boss that using normalisation is the best way to design a database but he's a hacker rather than a coder and he's taking some convincing.

If we take the typical Staff\Department scenario as an example (where it would be possible for a new member of staff to not yet be assigned to a department, say - (this is similar to a problem we are trying to iron out at the moment)).

My intuition and all the text books I've ever read would say do this:

Staff
StaffId *
Name

Department
DepartmentId *
Name

StaffDepartment
StaffId
DepartmentId

However he would want to do this:

Staff
StaffId *
Name
DepartmentId (Nullable)

Department
DepartmentId *
Name

I can see his point-of-view but still want to do it the normalised way. If I can convince him that the performance of the database is better when normalised then it would sway him, but I'm no expert when it comes to indexes and table scans and the like.

Could somebody please explain if and why a normalised database performs better.

Many thanks in advance.

I dont think explaining will help. You are a smart person, and i may suggest a different solution (it does help, if used the right way):

1. Go to your boss' office and say hello to him.
2. Pick a heavy book from his desk.
3. Hit him on the head with it.

In other words, dont waste your time explaining rather simple things.

Hi

First off good luck convincing him that you are correct. (You are correct)


Relational databases should contain minimum amout of repeated data for following reasons.

a) Your bosses solution will need more disk space which meabs records take longer to load etc. Try calculating extra disk space required. You know how many records and field length allocated for department.

b) Multiple department entries (your bosses method) will lead to spelling mistakes will lead to bad reporting, etc.

Your method will allow for the department to be entered once. One possible spelling mistake, one place to update, etc.

Your method leads to easier reporting, less errors, less disk space used, quicker running.

Let us know how you get on please.

Denis

Denis is Absolutely Right. Still, if his method doesn't work, I highly recommend mine.

Not any old book will do; please use "A Relational Model of Data for Large Shared Data Banks" by Dr Edgar F Codd.