Data Warehouse Interview Questions and Answers
Question - 1 : - What is Datawarehousing?
Answer - 1 : -
A Datawarehouse is the repository of a data and it is used for Management decision support system. Datawarehouse consists of wide variety of data that has high level of business conditions at a single point in time.
In single sentence, it is repository of integrated information which can be available for queries and analysis.
Question - 2 : - What is Business Intelligence?
Answer - 2 : -
Business Intelligence is also known as DSS – Decision support system which refers to the technologies, application and practices for the collection, integration and analysis of the business related information or data. Even, it helps to see the data on the information itself.
Question - 3 : - What is Dimension Table?
Answer - 3 : -
Dimension table is a table which contain attributes of measurements stored in fact tables. This table consists of hierarchies, categories and logic that can be used to traverse in nodes.
Question - 4 : - What is Fact Table?
Answer - 4 : -
Fact table contains the measurement of business processes, and it contains foreign keys for the dimension tables.
Example – If the business process is manufacturing of bricks
Average number of bricks produced by one person/machine – measure of the business process
Question - 5 : - What is Data Mining?
Answer - 5 : -
Data Mining is set to be a process of analyzing the data in different dimensions or perspectives and summarizing into a useful information. Can be queried and retrieved the data from database in their own format.
Question - 6 : - What is OLTP?
Answer - 6 : -
OLTP is abbreviated as On-Line Transaction Processing, and it is an application that modifies the data whenever it received and has large number of simultaneous users.
Question - 7 : - What is OLAP?
Answer - 7 : -
OLAP is abbreviated as Online Analytical Processing, and it is set to be a system which collects, manages, processes multi-dimensional data for analysis and management purposes.
Question - 8 : - What is ODS?
Answer - 8 : -
ODS is abbreviated as Operational Data Store and it is a repository of real time operational data rather than long term trend data.
Question - 9 : - What is the difference between View and Materialized View?
Answer - 9 : -
A view is nothing but a virtual table which takes the output of the query and it can be used in place of tables.
A materialized view is nothing but an indirect access to the table data by storing the results of a query in a separate schema.
Question - 10 : - What is the difference between OLTP and OLAP?
Answer - 10 : -
Followingare the differences between OLTP and OLAP:
| OLTP | OLAP |
| Data is from original data source | Data is from various data sources |
| Simple queries by users | Complex queries by system |
| Normalized small database | De-normalized Large Database |
| Fundamental business tasks | Multi-dimensional business tasks |