Data Warehousing Interview Questions

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8) What is OLAP?
OLAP stands for Online Analytical Processing and is a system that collects, manages, and processes multidimensional data for analysis and management purposes.

9) What is the difference between OLTP and OLAP?
Below are the differences between OLTP and OLAP:

OLTP OLAP
Data taken from original data source Data taken from various data sources
Simple user queries Complex queries on the system
Normalized small database Denormalized Large Database
Fundamental business challenges Multidimensional business problems
10) What is ODS?
ODS stands for Operational Data Warehouse and canada consumer mobile number list is a repository of real-time operational data rather than long-term trend data.

11) What is the difference between a view and a materialized view?
A view is nothing but a virtual table that accepts the output of a query and can be used instead of tables.

A materialized view is nothing but an indirect access to the table data by storing the query results in a separate schema.

12) What is ETL?
ETL is short for Extract, Transform, and Load. ETL is a software that is used to read data from a specified data source and extract the desired subset of data. It then transforms the data using rules and lookup tables and transforms it into the desired state.

The load function is then used to load the retrieved data into the target database.

13) What is VLDB?
VLDB is short for Very Large Database and is more than one terabyte in size. These are decision support systems that are used to serve a large number of users.