I need to produce a data model diagram with attribute names for the
following scenario which include cardinalities in the diagram.

Richard's Construction has hired you to produce a data model to aid
them in creating a database to store information on the houses they are
working on and the people working on them.

Richard builds houses in remote communities and hires a number of
workers to aid in the construction. Each worker is paid based on the
number of hours they work and the position they are working on. After a
certain number of hours in any week, they are paid double time for
overtime. Richard is also interested in compiling reports on who worked
on which house and for how long for performance statistics.

If a worker leaves before his contract is complete, he is responsible
for reimbursing Richard for a portion of his travel expenses. This must
be captured in the data base as well.

Richard maintains a number of houses for his people to stay in while
working. These houses are eached managed by one of the senior workers
whe recieves a bonus for managing the house in addition to their
regular duties. The workers staying in the house are deducted a minimal
amount for food and lodging from each paycheck for the number of days
they spend in the house.

Richard is also worried about the utilization of his houses. He wants
to be able to get reports on a regular basis showing the number of
people staying in each house and a warning if the number of people in a
house falls below a preset limit for a length of time.

PLEASE ADVICE YOUR PROPOSAL...Many Thanks

On 7 Jul 2006 12:25:20 -0700, soalvajavab1 (AT) yahoo (DOT) com wrote:

That is right. YOU need to.

Some of us would be willing to give guidance, but the work must
be yours. We are not going to do your homework for you.

[snipped homework problem]

Sincerely,

Gene Wirchenko

Gene Wirchenko wrote:

Absolutely!

However, if it was me (and therefore this might not be right!), I'd
start by laying out a few keywords on a piece of paper (or in my head)
- like 'projects','workers','positions','hours' (or maybe
'project_worker_hours'),'accommodation',etc. - and try to attach to
each of those ideas each of the pieces of information that I'm likely
to need to know. Then I'd maybe draw a few lines between each of the
keywords to try and express the likely sorts of relationships between
them.

Hey presto, before you know it you've got a data model!

The first job is to make a list of the requirements of the Infomation
System.

For instance, the business requirements for pay mean that you need a payroll
system.

Maintain a list of all employees
Maintain a job title for all employees
Maintain a rate of pay for all job titles
Keep track of where each employee lives
Keep track of the number of employees in each house
Keep track of House occupation limit.
Maintain assignment of senior employees as House Supervisors
Keep track of hours worked
Pay normal pay for XX hours or less
Pay 1.5 pay for Over XX hours
Pay bonus pay for house supervisors

So everytime you think you have everything reread the written requirements
and see if you need to add something to your list. I left a few things out
on purpose. For instance it said something about travel expenses, but it did
not say what rate of pay travel expenses are. It also mentioned Contracts,
length of contracts, are repaying travel pay.

As you see some details are left out. This is when you have to play systems
analyst and ask for more details. You dont really know what is in a
specific Contract. For instance how do you control who lives in which house
and how house assignments are controlled. Also there was not mention of the
supervisor to Subordinate structure and whether supervisors get salary or
are payed hourly. Possibly you might have Crewchiefs or gourp-leaders.
There are a few other holes where some filling in of information is needed.

Data Model is kind of vague term. It can be a logical model with just data
objects. Then you add data elements to the objects they belong to. Think
of an object as a big box with a purpose. Then the Box has data elements
that describe the object, the whole object, and only the object. If this
does not hold true then maybe your object is more than one object.

Then you can take this further. For every entity you can describe it, you
can indicate what kind of data it is and what the charcteristics of each
object are. Is it required, is it a key, is it a foreign key.

The level of the modeling has to be determined. The data model can go in
different directions. Some projects take the data model and start to do
process modeling and then maybe Gart Diagrams or Program Specifications.

Pay attention to the Output. The object of a data structure is not to put
data into a structure, but to get reports or output out of a data structure.

The Proposal is probably an initial proposal. When you outline your
seggested project development in a general way. It is probably not detailed
project plan which every task mapped out in Microsoft Project, but a kind of
general proposal. This might include more specific but general terms like
Develop a information system with the following components: HR, PAYROLL,
CONTRACTS, ASSET MANAGEMENT, ETC. It probably has to have some of your
justification for your proposal and it may need some alternatives and
address the Scope of the project. Payroll may be out of scope if you use an
external payroll system where you just supply the number of hours, etc.
<soalvajavab1 (AT) yahoo (DOT) com> wrote