DIFFERING DATABASE MODELS
To meet the needs of today's business world, there are four main types 
of database models. Each of these models may be used independently or 
in conjunction to form a business application.

OLTP
The Online Transaction Processing (OLTP) model is used for fast 
transactional processing. An inventory/sales application is an example 
of this type of system. The OLTP model is usually highly normalized for 
business, with smaller tables usually giving way to smaller 
transactions.

ODS
The Operational Data Store (ODS) stockpiles business data on a day-to-
day basis. It tends to summarize and store data from OLTP systems with 
very little historical information. This type of database application 
may hold data outside of the SQL Server in other storage resources. 
This data would be considered supplemental information.

DATA WAREHOUSE
Sometimes referred to as decision support systems, the data warehouse 
is used to hold all of an organization's data as well as its history. 
An example of this could be that the histories of both the above OTLP 
system as well as a human resources database are stored within the same 
warehouse application. These models are usually very large denormalized 
databases. History is sometimes stored as summary information.

DATA MART
The data mart model is a specific subset or segment of the data 
warehouse. This usually comes from the data warehouse and provides 
information at the departmental level. The data mart is where online 
analytical processing (OLAP) usually takes place. OLAP consists of 
cubes that give the user a three-dimensional view of the data usually 
over a given time period.

------------------------------------------