Wednesday 4 January 2012

Why to implement Data Warehousing?


Why to implement Data Warehousing?

1.       To perform server/ disk bound tasks associated with query and reporting on server / disks not used by transaction processing system.

It means,
Every organization has different databases for Transactions, Query and Reporting purpose.
This is because, if they generate reports on the Transactional Database, it will be varying for every hour.
And if transaction Database stores huge amount of data, then perform select will consume more time and also it will internally affect transaction process.
Hence they can't exactly analyze the up's and Down's of their Business.
       
But if they perform the Query and Generate reports on static data which varies less frequently, they can analyze their business in better way.

This is the main reason for Evaluation of Data Warehousing.

2.       To use data models and/ or server technologies that speed up query processing and reporting which are not appropriate for transaction processing.

There are several techniques to speed up the query process like Star Schema, Using Clusters, Bit map indexing etc.. But All of them effect the performance of DML operations on the data. Hence if they are implemented on the transactional database, entire database process will be collapsed.
 There a few more server technologies which improves transaction processing but reduces the query and reporting process.  Hence the Organizations or firms started using Data Warehouse for separating the business logic from data to data transaction process.

3.       To provide an environment where a relatively small amount of knowledge of the technical aspects of database technology is required to write and maintain queries and reports and/ or to provide a means to speed up the writing and maintaining of queries and reports by technical personnel.

4.       To provide a repository of "Cleaned Up" transaction processing system data that can be reported against and that doesn't necessarily require fixing the transaction processing systems.


5.       To make it easier, on a regular basis to query and report data from multiple transaction processing systems and/ or from external data that must be stored for Query / Report purposes only.

6.       To provide a repository of transaction processing system data that consists data from a longer span of time than can efficiently be held in a transaction processing system and/ or to be able to generate reports " As Was" as of a previous point in time.

7.       To prevent persons who only need to query and report transaction processing system data from having any access whatsoever to transaction processing system databases and logic used to maintain those databases.

Example:
In order to store data over the years, many application designers in each branch have made their individual decisions as to how an application and database should be built. So source systems will be different in naming conventions, variable measurements encoding structures, and physical attributes of data.

Consider a bank that has got several branches in several countries, has millions of customers and the lines of business of the enterprise are savings, and loans. The following example explains how the data is integrated from source systems to target systems.





In the aforementioned example, attribute name, column name, datatype and values are entirely different from one source system to another. This inconsistency in date can be avoided by integrating the data into a data warehouse with good standards.





In the above example of target data, attribute name, column name, and datatypes are consistent throughout the target system. This is how data from various is integrated and accurately stored into the data warehouse.











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