---
title: "Define data warehousing and creation process"
subject: "Data Mining"
chapter: 1
key: "semester_7/data_mining:dw-creation-process"
source: https://www.bctengineer.com/q/semester_7/data_mining/dw-creation-process
site: BCT Engineering
---

# Define data warehousing and creation process

Data Mining · Chapter 1: Introduction

- Asked in: year not given, 3+3+4 marks
- Video: [What is a Data Warehouse -  Explained with real life example | datawarehouse vs database (2020)](https://www.youtube.com/watch?v=jmwGNhUXn_o) — IT k Funde
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/data_mining/dw-creation-process
- Whole chapter: https://www.bctengineer.com/md/semester_7/data_mining/chapter-1

## Question

How do you define data warehousing? Why do any organization need a data warehouse? Explain the process of creating a data warehouse.

## Short answer

Data warehousing integrates heterogeneous data into a subject-oriented historical repository for decision support. Organizations need it for a consistent view, historical analysis, improved quality, and competitive advantage. Creation involves requirement analysis, source identification, dimensional modeling, ETL development, database building, access layer setup, testing, deployment, and maintenance.

## Answer

#### Data warehousing
**Data warehousing** is the process of constructing and using a data warehouse: collecting data from multiple heterogeneous sources, cleaning and integrating it, storing it in a subject-oriented historical repository, and providing tools for query, OLAP and mining to support decision making.

#### Why an organisation needs a data warehouse
- To get one consistent view of data scattered across many systems.
- To analyse historical trends without disturbing operational systems.
- To improve data quality and reporting speed.
- To support planning, forecasting and data mining for competitive advantage.

#### Process of creating a data warehouse
1. **Requirement analysis**: identify business goals, subject areas, users and key queries.
2. **Identify data sources**: operational databases and external data to be included.
3. **Design the model**: choose architecture (top-down/bottom-up), design dimensional schema (facts, dimensions, granularity) and metadata.
4. **ETL design and development**: extract data from the sources, clean it (errors, duplicates, missing values), transform it (formats, codes, derived values) and load it.
5. **Build the warehouse database**: create tables, indexes, aggregates and data marts; choose hardware and DBMS.
6. **Build access layer**: OLAP server, report, query and mining tools.
7. **Test and deploy**: check data accuracy and performance, train users, release.
8. **Maintain**: periodic refresh, backup, security, tuning and growth.

```text
 Plan -> Design -> Build ETL -> Load -> Test -> Deploy
   ^                                              |
   +------------- Maintain / refresh <------------+
```

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What is data warehousing?
   A. Writing reports on OLTP
   B. Constructing and using a warehouse: collecting, cleaning, integrating data and providing query, OLAP and mining tools
   C. Only buying hardware
   D. Deleting old data
   Answer: B. It covers both building and using the warehouse for decision support. (Key point: Data warehousing definition)

2. What is the first step in creating a warehouse?
   A. Requirement analysis of goals, subjects, users and key queries
   B. Testing
   C. Loading data
   D. Training users
   Answer: A. Requirements guide all later design. (Key point: First step)

3. What is decided in the design-the-model step?
   A. Report colours
   B. Architecture (top-down/bottom-up), dimensional schema, granularity and metadata
   C. User passwords
   D. Backup times
   Answer: B. Design covers architecture, facts, dimensions and granularity. (Key point: Design stage)

4. Why does an organisation need a warehouse?
   A. To reduce data quality
   B. To get a consistent view and analyse history without disturbing operational systems
   C. To remove its operational systems
   D. To avoid reporting
   Answer: B. It integrates scattered data and supports analysis separately. (Key point: Why needed)

## Related in Data Mining

- [Data warehouse, data mart and need](https://www.bctengineer.com/question.md?key=semester_7%2Fdata_mining%3Awarehouse-datamart-need) — Data Mining, chapter 1
- [National data warehouse process architecture](https://www.bctengineer.com/question.md?key=semester_7%2Fdata_mining%3Anepal-national-data-warehouse) — Data Mining, chapter 1
- [Typical process flow in warehouse](https://www.bctengineer.com/question.md?key=semester_7%2Fdata_mining%3Adw-process-flow) — Data Mining, chapter 1
- [Data warehouse schemas](https://www.bctengineer.com/question.md?key=semester_7%2Fdata_mining%3Adw-schema-types) — Data Mining, chapter 1
- [Data warehouse architecture and components](https://www.bctengineer.com/question.md?key=semester_7%2Fdata_mining%3Adw-architecture-components) — Data Mining, chapter 1
- [Short note: Noise in data warehouse](https://www.bctengineer.com/question.md?key=semester_7%2Fdata_mining%3Anoise-in-dw-note) — Data Mining, chapter 2

## Related in other subjects

- [General process of creating a PCB](https://www.bctengineer.com/question.md?key=semester_5%2Finstrumentation_ii%3Apcb-creation-process) — Instrumentation II, chapter 8
- [Data warehouse and data mining](https://www.bctengineer.com/question.md?key=semester_8%2Finformation_system%3Adata-warehouse-data-mining) — Information System, chapter 4, asked 2×
- [Need for organization and its principles](https://www.bctengineer.com/question.md?key=semester_7%2Forganization_and_management%3Aorg-need-principles) — Organization and Management, chapter 1, asked 3×
- [Short note: data mining and warehousing](https://www.bctengineer.com/question.md?key=semester_8%2Finformation_system%3Adata-mining-and-warehousing-note) — Information System, chapter 4