Database Reference
In-Depth Information
The following table summarizes these three levels of design and two modeling mindsets,
leading to six different types of models:
Mindset
Relational
Dimensional
Key concepts focused on answer-
ing a set of business questions
such as, “Can I see
Gross Sales
Amount
by
Customer
?”
Key concepts and their business
rules such as, “Each
Customer
may place one or many
Orders
.”
CDM
All attributes required for a giv-
en application, neatly organized
into entities according to strict
business rules, and independent
of technology such as, “Each
Customer ID
value must return,
at most, one
Customer Last
Name
.”
All attributes required for a given
analytical application, focused on
answering a set of business ques-
tions and independent of techno-
logy, such as, “Can I see
Gross
Sales Amount
by
Customer
and
view the customer's first and last
name?”
LDM
Levels
of
Design
The LDM modified to perform
well in MongoDB. For example,
“Because there is a need to view
Gross Sales Amount
at a
Day
level, and then by
Month
and
Year
, we should consider embed-
ding all calendar fields into a
single collection.”
The LDM modified to perform
well in MongoDB. For example,
“To improve retrieval speed, we
need a non-unique index on
Cus-
tomer Last Name
.”
PDM
Note that it seems like there is a lot of work to do; we need to go through all three phases
- conceptual, logical, and physical. Wouldn't it be easier to just jump straight to building a
MongoDB database and be done with it?
Going through the proper levels of design will take more time than just jumping into build-
ing a MongoDB database. However, the thought process we go through in building the ap-