Datawarehouse

Data Warehousing Concepts
Venkat Jandhyala

2010

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1.1 INTRODUCTION

Data Warehousing Concepts

Based on the way the data is used, databases can be classified in two ways: the one that is used for transactions i.e. Online Transaction Processing (OLTP) and the one that is used for analysis Online Analytical Processing (OLAP). As the businesses these days contain huge amounts of data and the users are connected to these databases across the globe and round the clock the necessity for maintaining a separate database for the sake of analysis is very much clear. 1.2 OLTP DATABASES OLTP Databases are what we generally refer as ‘Databases’. These are the databases that contain day-to-day transactions. Typically, an OLTP database has hundreds of users connected to it and performing transactions round the clock. Most of the time, these transactions insert data in to the database. Examples are ATM Machines, Online Shopping, Online Application Filing, Online Railway Reservations … The ratio of the number of records being inserted are more than the number of records being updated or deleted. Hence these databases are optimized for insertions. These databases are normalized to reduce the redundancy of the data and increase performance while inserting the data. 3 rd Normalization Form is most commonly found in all types of businesses. Figure 1.1 shows the architecture of OLTP Databases.

Figure 1.1

Local Network or Internet OLTP Database (Normalized)

Users OLTP Database Architecture

Normalization is a refinement process for Online Transaction Processing (OLTP) data models. OLTP systems support the day-to-day operations of the financial institution. This is where trades
Venkat Jandhyala

are booked, executed and settled, where new product and customers are entered into the computer systems. The focus is on transaction management, entering changing and deleting records online in consistent manor. OLTP systems are not designed for analysis, reporting and...