By Rohit Agrawal Jan 2013

Is the data correct…?

Would table Cutomer_fact get loaded ever if Control Table has the following..?

What if the DW load frequency is daily and ETL execution time exceeds 24 hrs…?

2

CustID Title FirstName

LastName Gender DateOfBirth

Age

123 Mr Chris Joseph F 12/12/2000

22

DataBase Schema Table LastLoadDate LoadFrequency

Info_DB Customer Cust_fact 31/01/2012 D

Introduction

Testing Process

Focus Points

Challenges

Best Practices

3

Introduction

What ?• Exhaustive testing of a Data Warehouse during

its design and on an on-going basis

Why ?• Organisation decisions depend entirely on the

Enterprise data and the data should be of utmost quality

Where ?• Starting from Source till Reporting

When ?• Designing phase till Production

5

Testing Process

7

Focus Points

9

10

All Customer data from different bank branches are loaded

Insert data of Customers with age greater than 60 in senior citizen category

Error out the records if Customer does not belong to the Bank

11

Check February has 29 days in leap years only

A row in stage with AccountID=123 has the expected data in DW

Zip Code is of 6 digits, State names are properly abbreviated

12

Impact of Executing complex queries during data load/Rendering reports in 30 sec

Source system scheduling conflicts

Incremental loads as per Audit columns like LastUpdateDate/Incremental Flag

Voluminous data from heterogeneous sources

Data Quality not assured at source

Business knowledge. Organisation-wide Enterprise data knowledge may not be

feasible

Very high cost of quality .This is because, any defect slippage will translate into high

cost for the organisation

The heterogeneous data sources will be updated asynchronously

13

14

15

“If you torture data sufficiently, it will confess to almost anything.”

White Paper on Data Warehouse Testing- By Manoj Philip Mathen

Adventures with Testing BI/DW Application- http://msdn.microsoft.com

www.google.com

A Comprehensive Approach to Data Warehouse Testing- By Matteo Golfarelli

16

Thank You..!