Source Of Summary:

Lec.7.D. M. spring 2024.pdf

📚 Data Warehouse 🚀

🎯 1. Introduction to Data Warehousing

• Key Challenge:
  • Users struggle to find, understand, and use data due to:
    • Scattered data across networks ❌
    • Multiple versions with subtle differences 🔄
    • Poor documentation 📉
    • Unexpected results requiring transformations 📊
• User Needs:
  • Integrated enterprise-wide data 🌐
  • Value of summary/historical data 📅
  • "What-if" analysis capabilities 🧠

🧱 2. What is a Data Warehouse?

• Bill Inmon’s Definition (1996):
  • A single, complete, and consistent store of data from diverse sources, designed for business context understanding.
• Alternative Definitions:
  • A Decision Support System (DSS) tool for organizational decision-making 📈
  • A subject-oriented, integrated, time-variant, and nonvolatile collection of data 📊

🔍 3. Core Characteristics of Data Warehouses

🎯 3.1 Subject-Oriented

• Organized around subjects (e.g., sales, products, customers) 🛒
• Focuses on modeling and analysis for decision-makers 📋
• Excludes irrelevant data for simplicity ✂️

🔗 3.2 Integrated

• Combines heterogeneous data sources 🌐
• Ensures consistency via data preprocessing (e.g., resolving naming conflicts) 🔄