Common sense: difference between application database and data warehouse

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Introduction

I'm a beginner in this aspect. Basically, an app database and a data warehouse have in common is that they're both databases. However they serve for different purposes.

Diff

cite from resource 1:
The primary difference betwen you application database and a data warehouse is that while the former is designed (and optimized) to record , the latter has to be designed (and optimized) to respond to analysis questions that are critical for your business.

Application databases are OLTP (On-Line Transaction Processing) systems where every transaction has to be recorded, and super-fast at that. An application database system is designed to make sure that every transaction gets recorded within the time users are served.

Data warehouses are designed as OLAP (On-Line Analytical Processing) systems, these databases contain read-only data that can be queried and analyzed far more efficiently as compared to your regular OLTP application databases.

cite from resource 3 (read this resource linked below for a thorough understanding):

A common way of introducing data warehousing is to refer to the characteristics of a data warehouse as set forth by William Inmon:

• Subject Oriented
• Integrated
• Nonvolatile
• Time Variant

Figure 1-1 Contrasting OLTP and Data Warehousing Environments

Text description of the illustration dwhsg005.gif

More words on either one

An application database mainly serve for processing real time business data. It shows the whole picture of the business objects world. Every application should normally have an application database to gain any feature concerning persistence. However, a data warehouse is not a must for every business application. It is mainly for analysis of historical (or accumulated) data, and sometimes for real time. Because it is for analysis, it is normally configured as read only for the analysis that is based on it (that is, the end user). In data warehouses there're not only data directly reflecting the status of business objects of some time, but also (and mainly this kind) data derived from business objects data.

data in data warehouse:
Raw data: mappings of business object data
Summary data: monthly statistics
Meta data: day, month, year, etc

Further reading:     

1. Business Intelligence: What is Data Mining?
2. Business Intelligence - What is it?
   

Resources

1. Database vs. Data Warehouse
2. GeekInterview.com  >  Interview Questions  >  Data Warehousing
3. Oracle9i Data Warehousing Guide Release 2 (9.2)