Interview Questions : DataWareHouse - Part6

What is BUS Schema?
BUS Schema is composed of a master suite of confirmed dimension and standardized definition if facts.

What are the methodologies of Data Warehousing?
Every company has methodology of their own. However, to name a few SDLC Methodology, AIM methodology is standard used.

Difference between OLTP and OLAP

OLTP:

Online Transactional Processing databases are functional orientated, they are designed to provide real-time responses from concurrent users and applications. To be more specific, OLTP databases must provide real-time concurrent (multi-threaded) processing of all SQL transaction (writes/updates and reads). Another characteristic of an OLTP database, is the fact that its state (underlying data) is constantly changing. Examples of OLTP are databases that support e-commerce applications.

OLTP databases are highly Normalized relational databases. This means that there is very little or no data redundancy. This ensures data consistency (part of the ACID standard). Normalization is the process of arranging data into logical, organized groups of tables, reducing data repetition or going so far as to completely eliminating it. As a result the data is logically grouped into tables, and these tables form relationships with one another through the use of primary and foreign keys. There are different levels of normalization and OLTP data models usually meet the 3rd Normal Form also known as the Entity Attribute Relationship Model.