What is a Data Warehouse?

A Data Warehouse is a system used to store large amounts of data from different sources in one place. It is mainly used for reporting and analysis, not for daily operations.

Think of it like a central storage where all business data is collected, cleaned, and organized so companies can make better decisions.

Why Do We Need a Data Warehouse?

In a company, data comes from many systems like:

• Websites

• Mobile apps

• Databases

• Sales systems

These systems are separate and messy. A data warehouse helps to:

• Combine all data into one place

• Clean and organize data

• Make data easy to analyze

How It Works (Simple Flow)

1. Data Collection
   Data is taken from different sources (databases, APIs, files)

2. Data Processing (ETL)

   • Extract → Get data

   • Transform → Clean and format data

   • Load → Store in warehouse

3. Storage
   Data is stored in a structured format (tables)

4. Analysis & Reporting
   Tools like Power BI, Tableau, or SQL are used to analyze data

Key Features of Data Warehouse

• Centralized → All data in one place

• Historical Data → Stores past data for years

• Optimized for Queries → Fast for analysis

• Read-heavy system → Mostly used for reading, not writing