Pingahla Interview Questions and Answers

SQL query is a command used to retrieve data from a database.

• SQL stands for Structured Query Language

• Queries can be used to retrieve specific data from a database

• Queries can also be used to update, insert, or delete data from a database

• Example: SELECT * FROM customers WHERE city = 'New York'

ETL projects involve extracting, transforming, and loading data from various sources into a target system.

• ETL projects are used to integrate data from multiple sources into a single system

• They involve extracting data from source systems, transforming it to meet the target system's requirements, and loading it into the target system

• Examples of ETL projects include data warehousing, business intelligence, and data migrat...read more

Dimension modelling is a technique used in data warehousing to organize and structure data for efficient analysis.

• Pros: improves query performance, simplifies data analysis, provides a clear understanding of data relationships

• Cons: can be complex and time-consuming to implement, requires a deep understanding of the data being modeled

• Examples: star schema, snowflake schema

Optimization techniques for data loading

• Use parallel processing to load data faster

• Optimize database queries to reduce loading time

• Use compression techniques to reduce data size

• Implement caching to reduce data retrieval time

• Use incremental loading to load only new or updated data

A DWH for a University with table relationships

• Create a student table with student ID as primary key

• Create a course table with course ID as primary key

• Create a faculty table with faculty ID as primary key

• Create a enrollment table with student ID and course ID as foreign keys

• Create a teaching table with faculty ID and course ID as foreign keys