Online Analytical Processing
OLAP (or Online Analytical Processing) has been
growing in popularity due to the increase in data volumes and the recognition
of the business value of analytics.
OLAP allows business users to slice and dice data at
will. Normally data in an organization is distributed in multiple data sources
and are incompatible with each other. A retail example: Point-of-sales data and
sales made via call-center or the Web are stored in different location and
formats. It would a time consuming process for an executive to obtain OLAP
reports such as - What are the most popular products purchased by customers
between the ages 15 to 30?
Part of the
OLAP implementation process involves extracting data from the various data
repositories and making them compatible. Making data compatible involves
ensuring that the meaning of the data in one repository matches all other
repositories. An example of incompatible data: Customer ages can be stored as
birth date for purchases made over the web and stored as age categories (i.e.
between 15 and 30) for in store sales.
It is not always necessary to create a data
warehouse for OLAP analysis. Data stored by operational systems, such as
point-of-sales, are in types of databases called OLTPs. OLTP, Online
Transaction Process, databases do not have any difference from a structural
perspective from any other databases. The main difference and only, difference
is the way in which data is stored.
Examples of OLTPs can include ERP, CRM, SCM,
Point-of-Sale applications, Call Center.
OLTPs are designed for optimal transaction speed.
When a consumer makes a purchase online, they expect the transactions to occur
instantaneously. With a database design, call data modeling, optimized for
transactions the record 'Consumer name, Address, Telephone, Order Number, Order
Name, Price, Payment Method' is created quickly on the database and the results
can be recalled by managers equally quickly if needed.
OLAPs have a different mandate from OLTPs. OLAPs are
designed to give an overview analysis of what happened. Hence the data storage
(i.e. data modeling) has to be set up differently. The most common method is
called the star design.
The central table in an OLAP start data model is
called the fact table. The surrounding tables are called the dimensions. Using
the above data model, it is possible to build reports that answer questions
such as:
- The supervisor that gave the most discounts.
- The quantity shipped on a particular date, month, year or quarter.
- In which zip code did product A sell the most?
To obtain answers, such as the ones above, from a
data model OLAP cubes are created. OLAP cubes are not strictly cuboids - it is
the name given to the process of linking data from the different dimensions.
The cubes can be developed along business units such as sales or marketing. Or
a giant cube can be formed with all the dimensions.
Sanket Kadam - 14165
Operations Batch
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