Data warehousing concepts:
1) What is Data warehouse?
Data warehouse is relational database used for query analysis and reporting. By definition data
warehouse is subject-oriented, integrated, non-volatile, time variant.
Subject oriented: Data warehouse is maintained particular subject.
Integrated: Data collected from multiple sources integrated into a user readable unique format.
Non volatile: Maintain Historical date.
Time variant: data display the weekly, monthly, yearly.
2) What is Data mart?
A subset of data warehouse is called Data mart.
3) Different between data warehouse an data mart?
Data warehouse is maintaining the total organization of data. Multiple data
marts used in data
warehouse. Where as data mart is maintained only particular subject.
4) Difference between OLTP and OLAP?
OLTP is online transaction processing.This maintains current transactional data. That means insert,
update and delete must be fast.
5) Explain ODS?
Operational data store is a part of data warehouse. This is maintained only current transactional
data.ODS is subject oriented, integrated, volatile, current data.
6) Difference between power center and power mart?
Power center receive all product functionality including ability to multiple register servers and metadata
across the repository and partition data. One repository multiple informatica servers. Power mart
received all features expect multiple register servers and partition data.
7) What is a staging area?
Staging area is a temporary storage area used for transactions integrated and rather than transaction
processing when ever your data put in data warehouse you need to clean and process your data.
8) Explain additive, semi-additive, non-additive facts?
Additive fact: Additive Fact can be aggregated by simple arithmetical additions.
Semi-Additive fact: semi additive fact can be aggregated simple arithmetical
