Normalization from an excel form

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Normalization from an excel form

zesralem_sie

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Points: 187
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October 14, 2012 at 5:17 pm

#263285

Hey guys, I have some problems with normalizing the data.
Could you take a look at this file
http://speedy.sh/YtK9G/example.xlsx
These is the list of attributes: week site day timeSlot employee role sick totalHrs
Week and site will be a compound key.
A lot of things confuses me here so I'd really appreciate your help.
Thanks in advance 🙂

Viewing 5 posts - 1 through 4 (of 4 total)

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Andrew G SSChampion Points: 12809 More actions · Answer 1

If you take a look at the Microsoft example database called AdventureWorks, it has a very similar structure to what you're looking for:

http://msdn.microsoft.com/en-us/library/ms124438%28v=sql.100%29.aspx

Specifically look at the HumanResources.Shift, HumanResources.Employee

You need separate tables for Site (ID name location purpose), Employee (ID name occupation), Day (ID, Name), EmploymentRole (ID, rolename), TimeSlot(ID Start and end times - no dates), Sick(Maps Timeslot & Employee), ShiftRecord (Maps EmpID, DayID, TimeSlotID, RoleID)

Then use excel to link to these tables with dropdown selection list (MyList function).

zesralem_sie SSC Enthusiast Points: 187 More actions · Answer 2

Thanks.

That thing exactly confuses me, because trying to do top - down approach for this case I know I will need a separate table for almost every attribute here.

But I'm not really quite sure how to go about bottom-up approach. I know the rules of normalization, and that should be enough, but still...

UNF: week site day timeSlot* employee* role* sick* totalHrs*

Let me try do the 1NF (I should break out repeated groups to form new group and include original key as a foreign key), so:

1NF:

1) week site day (should I put the day attribute here? the data itself does not repeat in the form)

2) employee week site timeSlot role sick totalHrs

What do you think about it? Is that ok?

Andrew G SSChampion Points: 12809 More actions · Answer 3

Oh I see, OK, I don't think 1 is correct, with {day} there you'll have non unique week site keys, or am I jumping past 1nf..

IMO, I think it should be

week site day timeSlot* employee*

Week day employee sick

Employee week totalhours

Its getting a little into 2nf I think though.. but you can still break out further since employee does not depend on week site day etc.. so possibly OK.

zesralem_sie SSC Enthusiast Points: 187 More actions · Answer 4

Thanks again for the response.

I forgot to mention that I have to get this thing all the way to 3NF.

There's no employee role in your suggestion.

I've attempted to go a step further and get it to 2NF and I got:

week

site

day

employee role

timeSlot

site week day employee timeSlot

employee week totalHours

Bold attributes are assumed to be IDs.

Underlined ones are foreign keys.

As you see I'm still confused. The set of attributes is so varied that I'm tempted to jump in and split them up immediately.

Unfortunately I have to prepare the formal solution and what should be added in 1NF is supposed to be in 1NF, what in 2NF in 2NF. Else I'll lose some points while being graded 🙂

Thank you again for your time 🙂