Google Answers Logo
View Question
Q: Systems Analysis and Design Methods ( Answered,   0 Comments )
Subject: Systems Analysis and Design Methods
Category: Computers > Programming
Asked by: newman-ga
List Price: $2.50
Posted: 05 Oct 2002 11:02 PDT
Expires: 04 Nov 2002 10:02 PST
Question ID: 72919
How do I prepare an Entity Definition Matrix and a Context Data Model?
Subject: Re: Systems Analysis and Design Methods
Answered By: willie-ga on 06 Oct 2002 03:26 PDT
Hello there

You've asked a big question, but I'll give you an overview and links
that'll get you going

The Entity Definition Matrix is just a list of all the entities on
your system, with a short description. An entity is something you want
to collect data on, and often refers to something physical, like a
person, a place or a form eg in a simple order processing system, you
might have entities like the following

Customer         Person making the order
Order            The customers order for goods
Store            The place where the order will be sourced from
Invoice          The bill the customer will receive
Accounts         The place from where the bill is issued

The Entity Definition Matrix is therefore just a table, two columns,
one for your entity name, one for its description.
You'll find a template online here (

and theres a nice example here ( )

THe CONTEXT DATA MODEL is a graphical representation of these entities
and their relationship with each other  eg in the above example, it
will show that a customer makes an order, that an order is sourced
from the store, that the store tells accounts about the order and that
accounts issue an invoice, that goes to the customer.

This is generally done in the form of a diagram, with the entities in
boxes, and lines identifying relationships between them. ( A tip is to
make all the boxes containing the entity names the same size, and all
the lines the same length. It looks neater that way)

The example above is a simple one and would make an easy diagram to
draw using the following relationships. (Remember that entity names go
in rectangular boxes, and lines are solid )

CUSTOMER --makes--> ORDER --sends to--> STORE --informs --> ACCOUNTS
--produces--> Invoice --sends to--> CUSTOMER

In more complex cases, you can define that the customer can make many
orders, sourced from many stores, and you can define entities looking
after customer complaints, unfilled orders, cancelled orders etc. You
can see how the model can build up quickly, but that's all the subject
for a much bigger (and costlier) question :)

place in a study phase model that includes only entities and
relationships, but no attributes ie, you're not describing any of the
detail of the entities, only what they are, and how they relate to
each other.

You'll find a very good overview of a terms used in Analysis and
Design and Data Modelling in particular at the following ( )

Google Search Strategy
There are no comments at this time.

Important Disclaimer: Answers and comments provided on Google Answers are general information, and are not intended to substitute for informed professional medical, psychiatric, psychological, tax, legal, investment, accounting, or other professional advice. Google does not endorse, and expressly disclaims liability for any product, manufacturer, distributor, service or service provider mentioned or any opinion expressed in answers or comments. Please read carefully the Google Answers Terms of Service.

If you feel that you have found inappropriate content, please let us know by emailing us at with the question ID listed above. Thank you.
Search Google Answers for
Google Answers  

Google Home - Answers FAQ - Terms of Service - Privacy Policy