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
ENTITY DESCRIPTION
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
etc
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 (
schultz.la.unm.edu/CS220F02/Files/
Entity%20Definition%20Matrix%20V5.0.doc
and theres a nice example here (
www.oakland.edu/~wdsnyder/data/mis316project.doc )
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 :)
Both ENTITY DEFINITION MATRIXEs and DATA CONTEXT MODELs usually take
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 (
http://www.emu.edu.tr/~balkan/Ders6.htm )
Google Search Strategy
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