Data warehouse vs data lake in HLD - Quick Revision & Key Differences

Recall & Review

beginner

What is a data warehouse?

A data warehouse is a system used to store structured data from multiple sources. It organizes data for easy analysis and reporting, often using tables and schemas.

beginner

What is a data lake?

A data lake is a storage system that holds large amounts of raw data in its original format, including structured, semi-structured, and unstructured data.

intermediate

Which type of data storage is best for fast, complex queries on cleaned data?

Data warehouses are best for fast, complex queries on cleaned and organized data because they use schemas and indexing.

intermediate

Why might a company choose a data lake over a data warehouse?

A company might choose a data lake to store all types of data in raw form, allowing flexibility for future analysis and machine learning without upfront structuring.

intermediate

What is a key difference in data processing between data warehouses and data lakes?

Data warehouses process data before storing it (ETL), while data lakes store raw data first and process it later (ELT).

Which system stores data in its raw, original format?

A Data warehouse

B Data lake

C Relational database

D Cache

Data lakes store raw data in its original format, unlike data warehouses which store processed data.

What type of data is primarily stored in a data warehouse?

A Structured data

B Unstructured data

C Raw data

D Binary data

Data warehouses store structured data that is cleaned and organized for analysis.

Which process is commonly used before loading data into a data warehouse?

A ETL (Extract, Transform, Load)

B ELT (Extract, Load, Transform)

C Streaming

D Caching

ETL means data is extracted, transformed (cleaned and structured), then loaded into the warehouse.

Which system is more flexible for storing different data types?

A Data warehouse

B OLAP cube

C Data mart

D Data lake

Data lakes can store structured, semi-structured, and unstructured data, making them more flexible.

Which system is optimized for fast analytical queries on cleaned data?

A Data lake

B File system

C Data warehouse

D NoSQL database

Data warehouses are designed for fast, complex queries on cleaned and organized data.

Explain the main differences between a data warehouse and a data lake.

Think about data format, processing, and query speed.

Describe scenarios where a company might prefer a data lake over a data warehouse.

Consider flexibility and data variety.