Data Warehouse

TL;DR

Centralizes data from multiple, disparate systems to provide a single source of truth for analysis and reporting.
Uses ETL and data cleansing to integrate and ensure data quality.
Organizes data (e.g., star or snowflake schema) and applies security and performance optimizations for fast, controlled access.

Definition

A data warehouse is a central repository of integrated data from one or more disparate sources. It provides a consistent, single source of truth for data analysis and reporting.

Explanation

Data warehouses bring together data from multiple source systems and integrate it—typically through ETL (extract, transform, and load)—so the data is available in a consistent format for analysis and reporting. They apply data cleansing and validation to remove duplicates, fix errors, and enforce business rules, ensuring high data quality.

To enable efficient querying and analysis, data warehouses organize data into logical structures, commonly a star or snowflake schema. They enforce data security through authentication, access control, and encryption to protect sensitive information and limit access to authorized users. Performance for analysis and reporting is supported by techniques such as indexing, partitioning, and other optimization methods to allow fast and efficient data access.

Overall, a data warehouse provides an integrated, organized, secure, and high-performance repository that helps organizations understand data, identify trends, and make informed decisions.

Examples

Retail industry

A retail company may have multiple systems for managing sales, inventory, customer information, and marketing campaigns. These systems may be hosted on different platforms and use different data formats. A data warehouse can bring together data from all these systems, integrate it, and provide a single source of truth for data analysis and reporting. This can help the company better understand customer behavior, identify trends and opportunities, and improve decision making.

Healthcare industry

A hospital may have multiple systems for managing patient records, medical treatments, billing, and insurance information. These systems may be siloed and not easily accessible for data analysis and reporting. A data warehouse can bring together data from all these systems, integrate it, and provide a single source of truth for data analysis and reporting. This can help the hospital better understand patient needs, identify trends and opportunities, and improve decision making.

ETL (extract, transform, and load)
Data integration
Data cleansing / data quality
Star schema
Snowflake schema
Indexing
Partitioning
Authentication
Access control
Encryption