Microsoft Windows

ETL Testing Roll Back post – Ask yourself and get ready to move to ETL Testing world

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Hello Folks

It had been long time I posted something through my Blog L , I’m really sorry for that 😦

jobinterview

I have met a person unknowingly in a common place, we were discussing about ETL testing and other stuffs and I told him I’m writing blogs about ETL Testing.  He was surprised and said that he is one visitor of my Blog. I am happy that I have met a unknown person who reads and benefited with my blog.

I have got few requests ‘Can you please share some of Interview Q & A?’

I replied them

“If you have hands on experience and if you would have mentioned in your CV about you skills and responsibilities then why you wanted to know about Q&A in ETL Testing”

Guys who are trying in ETL Testing domain, are thinking that if they know how to write SQL can clear the Interview and can get the job. Folks that’s not possible. I request you to think that ETL testing is not a different entity; your job is testing on whatever technology it is.

If you are taking an interview, please go through your CV and be strong on what you have mentioned. If you are asked other than what you have mentioned then please raise your hand ‘I’m sorry, I haven’t worked in it’

Ok let me come subject what I wanted to discuss here!!!

Here I’m going ask questions to myself to test my technical capability, if I win myself then I can win anywhere in the Globe, right guys?

So try to ask as much questions as possible to yourself!!!!

Q1

INTRV: Asik, Can you please let us know your roles and responsibilities in your previous project?

CAND: Hello, I’m from here and blaw, blaw, blaw………

Q2

INTRV: Asik, How you can scale yourself in writing in SQL from 1-5?

CAND:  [—-Fill your Best Answer here——]

Q3

INTRV: Asik, What all are the tools that you used in your ETL Projects?

CAND: [—-Fill your Best Answer here——]

Q4

INTRV: Asik, Can you please explain me the ETL architecture?

CAND: [—-Fill your Best Answer here——]

Q5

INTRV: What all are the Joins that you have worked so far? And can you please write down joins using two tables T1 and T2?

CAND: [—-Fill your Best Answer here——]

Q6

INTRV: Asik, what is the difference between Inner join and Outer Join?

CAND: [—-Fill your Best Answer here——]

Q7

INTRV: Asik, can you please explain me about the significance of Data Types in ETL Testing?

CAND: [—-Fill your Best Answer here——]

Q8

INTRV: Asik, I have a column as VARCHAR from source but corresponding target column is INTERGET, how you can write a query to check the target column?

CAND: [—-Fill your Best Answer here——]

Q9

INTRV: Asik, what is the significance of the Staging tables in the ETL loads?

CAND: [—-Fill your Best Answer here——]

Q10

INTRV: Asik, what is the difference between, copy records and duplicate records?

CAND: [—-Fill your Best Answer here——]

Q11

INTRV: Asik, what is the significance of Oracle Control tables in ETL Testing?

CAND: [—-Fill your Best Answer here——]

Q12

INTRV: Asik, what does it mean if you get a NULL, Blank, Space or 0 from Source?

CAND: [—-Fill your Best Answer here——]

Q13

INTRV: Asik, I have a VARCHAR column from source, this column can allow 0, suppose if source is sending 0000 instead of 0 , and the rule is we should not allow this record into target table. Does our SQL will stop this record if we write the condition as [Column <> 0]

CAND: [—-Fill your Best Answer here——]

Q14

INTRV: Asik, what is the difference between the Primary Index and Primary Key?

CAND: [—-Fill your Best Answer here——]

Q15

INTRV: Asik, what could be consequence if the reconciliation failed in the Day_01 load or Day_02 load?

CAND: [—-Fill your Best Answer here——]

Q16

INTRV: Asik, Why you wanted to test the DDL of any table?

CAND: [—-Fill your Best Answer here——]

Q17

INTRV: Asik, what is the difference between Data Definition Language and View Definition?

CAND: [—-Fill your Best Answer here——]

Q18

INTRV: Asik, as a tester what all are the access you required? And do you know the SQL query syntax to get the access?

CAND: [—-Fill your Best Answer here——]

 Q19

INTRV: Asik, what is the difference between DB level access, Table level access and view level access?

CAND: [—-Fill your Best Answer here——]

Q20

INTRV: Asik, What all are the steps you take to validate the Source Files? What is significance of Source File Names, Header, Trailer and Detailed Records?

CAND: [—-Fill your Best Answer here——]

Q21

INTRV: Asik, if you could not able to open a file manually by double click due to the file size? How you will access the file and look at the records?

CAND: [—-Fill your Best Answer here——]

Q22

INTRV: Asik, What is the High Severity defect that you raised so far in any ETL project and why you have classified as Sev-01?

CAND: [—-Fill your Best Answer here——]

Q22

INTRV: Asik, What is the High Priority defect that you raised so far in any ETL project and why you have classified as Sev-01?

CAND: [—-Fill your Best Answer here——]

Q23

INTRV: Asik, Explain about Inserts, Updates, Logical Deletes in any given ETL Projects?

CAND: [—-Fill your Best Answer here——]

Q24

INTRV: Asik, Why and what is necessity of Reference tables in any ETL Projects?

CAND: [—-Fill your Best Answer here——]

 Q25

INTRV: Asik, Can you modify Reference table data if you have Update access to the reference tables?

CAND: [—-Fill your Best Answer here——]

Q26

INTRV: Asik, What all are the Steps by which you can achieve the test data for a given scenarios?

CAND: [—-Fill your Best Answer here——]

Q27

INTRV: Asik, What is the difference between the Time Variant and Non time variant tables in any ETL Testing projects and how you will test it?

CAND: [—-Fill your Best Answer here——]

Q28

INTRV: Asik, Can you delete a table or Drop a table? What happened if we Drop a tables?

CAND: [—-Fill your Best Answer here——]

Q29

INTRV: Asik, What is the significance of Views in any ETL testing projects?

CAND: [—-Fill your Best Answer here——]

Q30

INTRV: Asik, Does a table contain more than one Primary Key? And Does a table contain more than one Primary Index?

CAND: [—-Fill your Best Answer here——]

Q31

INTRV: Asik, DBA has granted Select access to DB, does it mean that you have select access to all the tables sits in that DB?

CAND: [—-Fill your Best Answer here——]

 Q31

INTRV: Asik, if the target column is Integer (30) can you load a Varchar (30) into it?

CAND: [—-Fill your Best Answer here——]

Q32

INTRV: Asik, target Date column is constrained as DDMMYYYY but from source we are getting it as MMDDYYYY? What will happen to load job?

CAND: [—-Fill your Best Answer here——]

Q34

INTRV: Asik, What does it mean by Full-Snap shot and historical records?

CAND: [—-Fill your Best Answer here——]

Q35

INTRV: Asik, What does it mean Catch up logic involved in loads and how you will test it?

CAND: [—-Fill your Best Answer here——]

Q36

INTRV: Asik, What is the difference between Load projects and Extract projects?

CAND: [—-Fill your Best Answer here——]

Q37

INTRV: Asik, if the target column is defined as Decimal (4, 3), can you load the values as Decimal (4, 5)? Or can you load the values as Decimal (4, 3)

CAND: [—-Fill your Best Answer here——]

Q37

INTRV: Asik, What is the difference between Union and Union All? And where we want to use Union and where we want to use Union All?

CAND: [—-Fill your Best Answer here——]

 Q38

INTRV: Asik, What is the use of Cross Join? And what circumstances you use the Cross Join?

CAND: [—-Fill your Best Answer here——]

Q39

INTRV: Asik, What is the AutoSys comment to trigger the job, abort the job, hold the job?

CAND: [—-Fill your Best Answer here——]

Q40

INTRV: Asik, What is the significance of Group by functions in SQL and where we will use the Group by functions?

CAND: [—-Fill your Best Answer here——]

Q41

INTRV: Asik, How you can find the duplicates in the Staging tables?

CAND: [—-Fill your Best Answer here——]

Q42

INTRV: Asik, What is the difference between SET table and Multi Set tables? From where we can get these details?

CAND: [—-Fill your Best Answer here——]

Q43

INTRV: Asik, Can one View table refer another view table to create a new view table?

CAND: [—-Fill your Best Answer here——]

Q44

INTRV: Asik, Can one View table refer another view table to create a new view table?

CAND: [—-Fill your Best Answer here——]

 Q45

INTRV: Asik, What all are the common SQL Syntax errors you encountered and how you are resolved it?

CAND: [—-Fill your Best Answer here——]

Q46

INTRV: Asik, Do you have any idea what is Data Modeling?

CAND: [—-Fill your Best Answer here——]

Q47

INTRV: Asik, What is the difference between the Physical Design and Logical Design?

CAND: [—-Fill your Best Answer here——]

Q48

INTRV: Asik, What all are the Items available in a generic S2T?

CAND: [—-Fill your Best Answer here——]

Q49

INTRV: Asik, what does it mean if a column is mentioned as Value column in the S2T?

CAND: [—-Fill your Best Answer here——]

Q50

INTRV: Asik, Have I answered all of my basic questions to go to advanced questions?

CAND: I am still thinking and trying to answer few questions J

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What is Quality Assurance & Quality Control? and Who is PQA, CC, DPA in QA ???

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Hi All,

Quality Assurance and Quality Control

quality-blocks1

 

Being a Test Professionals we should know about QA and QC. What we are doing is actually Quality Control related stuff and what people involved in bringing up CMMI, ISO standards are Quality Assurance. Quality Assurance is more likely related to maintain the process in any given Project or Programme. Quality Control is nothing but giving the right product by verifying the requirements are covered and working as expected.

We know there are multiple levels of testing methods are spoken in the testing world and we have the methodology by which we need to execute them like System Test, Integration Test etc., and Methodology like Water fall, Iterative etc.,

Quality Assurance:

Let me explain what I know and aware of Quality Assurance:

There 3 different roles who will be responsible for assuring the process in any projects.

  1. PQA – Project Quality Analyst
  2. CC – Configuration Controller
  3. DPA – Defect Prevention Analyst

Project Quality Analyst – PQA role

A person who involved in this role needs to know the pre-defined industry standards of that Organization.

PQA’s Roles and Responsibilities

  1. Documents Naming Convention met as per the Industry Standard
  2. Names of who prepared , reviewed , approved the deliverables
  3. Reviews happened across all the Customer facing documents
  4. Review defects are found, fixed, verified and captured for Metrics
  5. Checking whether all the deliverables are kept in a Common place where the stake holders can access
  6. Checking all the necessary deliverables are prepared by the project team
  7. Checking the actual project delivery date and the date mentioned in the documents are same
  8. Checking the Stake Holders names, document owner names are mentioned correctly in all customer deliverables
  9. Differentiating the Customer facing deliverables and Internal audit specific deliverables are as per the industry standards
  10. Verifying the Entry Criteria and Exit Criteria of any Levels in SDLC are met and collecting the proofs for the same
  11. PQA’s will be involved in all levels of SDLC

Business Analyst Teams will have separate sets of Deliverables like Business Requirement documents, Business Understanding Documents, Requirement Traceability documents etc.,

  1. Development teams will have separate sets of Deliverables like High Level Design, Low Level Design , Functional Specifications etc.,
  2. Testing teams will have separate sets of documents like Test Plans, Test Conditions

The PQA should validate all the documents that supposed to be delivered to the Clients and maintain for internal audits

CC – Configuration Controller

Configuration Controller who controls the versions and the placement of the documents in tools like VSS – Microsoft Virtual Source Safe or Documentum etc.,

Configuration Controller Roles and Responsibilities

  1. CC’s are responsible of Creating the folder structures in VSS or Documentum

Like, in any Projects the following folders will be created to maintain the projects deliverables

  1. Project Kick off
  2. Minutes of Meeting
  3. Requirements
  4. Review Log
  5. Development

1.1.  High Level design

1.2. Low Level Design

1.3. Issue Log

1.4. Emails

6. Testing

1.1   Unit Testing

1.2   System Testing

1.3   System Integration Testing

1.4   User Acceptance Testing

6.Production Support

CC’s will have the Admin rights to Grant and Revoke access to folders.

Developers should not have access to the folders related to Testing and vice versa

  1. CC’s will maintain the Check in and Check out of the documents that goes into VSS
  2. CC’s will maintain the relevant documents are kept in corresponding folders in VSS

DPA – Defect Prevention Analyst

Defect Prevent Analysts will maintain the defects across the SDLC. For any raised defects the work flow should be maintained. Proper comments for those defects should be given when they are created. All high severity defects should be fixed from one Phase to next phase to being with.

As testers when we raise defects we need to concentrate on applying Defect Cause and Defect Type in any Defect Management tool. This will help DPA’s to classify the defects and comes up prevention tips.

Defect Cause – What is the root cause of the defect that is,

  • Is the defect caused because of the Upstream Source Data or Test Data
  • Is the defect caused because of Incomplete of Missing requirements
  • Is the defect caused because the Inconsistent Requirement
  • Is the defect caused because of the Code discrepancy
  • If you find any anomalies in any Documents then raise the defects to Artefacts
  • If any of your defects leads to Changes in the Requirement then please raise them as Change Request – CR can be on the Actual Business Requirement or on Design Changes.

Defect Type – Classifications of the Defects that is,

  • Is the defect related to Data Error
  • Is the defect related to Application Code
  • Is the defect related to Work Request
  • Is the defect related to Change Request
  • Is the defect related to Deployment
  • Is the defect related to Specification
  • Is the defect related to Artefact
  • Is the defect related to Production
  • Is the defect related to Process
  • Is the defect related to Environment
  • Is the defect related to Specification
  • Is the defect related to Requirements
  • Is the defect related to Reviews

DPA’s most prominent work is to prepare the CAPA – “Corrective Analysis and Preventive Actions”

DPA roles and Responsibilities

  1. DPA’s will collect the Metrics related to Defects in a periodic manner – Weekly, Monthly or Ad-hoc
  2. DPA’s will collect the defects by Defect classifications like in a given period of time how many defects are raised in Reviews, Code, Requirement Change and collects the cause of the defects
  3. Then using the metrics that was retrieved from any Defect Management tools, they design the Fish Bone diagram by filling the necessary details
  4. Using the Statistical tools like Minitab, they calculate the Defect Density of the defects from each phase
  5. Then they will create the Prevention actions on the areas where the Defect Density is above to the threshold limits.

Suppose if your Organization has the Defect Density threshold limit as 0.5 and your Defects under Review defect type is more than 0.5 then they will ask the Reviewers to do their work better to minimize the review defects at any levels of SDLC.

Cheers – Asik

Chapter 1 – Business Intelligence and Testing

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Business Intelligence and Testing!!!!

Intelligence is a very general mental capability that, involves the ability to reason, plan, solve problems, comprehend complex ideas, learn quickly and learn from experience.

Further simply put – It is “catching on,” “making sense” of things, or “figuring out” what to do

Business Intelligence is collecting the data from various sources of any organization to aid in planning, solving business problems and learning from experience there by taking proper decisions to expand its business and maximize profits.

Lets understand what a Warehouse is and how we can connect it to Information and Technology!!

Consider a person wants to set up a Provisional Store and he wants to know how to stock the Goods to maintain Supply and Demand life cycle. He’ll start a shop in a small room and gets goods in a limited quantity. 100 kg rice, 50 kg wheat, 100 kg dal, 3-4 varieties chocolates, 3-4 varieties of soaps and starts his business.

People start coming to his store and start buying things. In 15 days his stock is almost sold and then he analyses how the sales were. To achieve this he will maintain all the data on a paper and calculate (Add, Subtract, Multiply, Divide)

He’ll continue this for sometime and forecast the data he collected.

  • If analysis says that the goods are sold as per his calculations and he’s making profit then he’ll start getting goods in large quantities. Since the store is very small he cannot accommodate goods in bulk in the store so he will setup a warehouse where he can store all the goods. And small amount of goods required for a month, he’ll move them to the provisional store for selling.
  • If analysis says that the few goods in his shop are not sold and he is not making profit as expected but he is not making loss, then he can change the goods he is selling and try his analysis to ear profits
  • If analysis says that the goods in his shop are not sold at all and he is in huge loss then he might have to stop his business.

As a shopkeeper he needs to do analysis on the Goods available and the sales in the warehouse to continue or stop buying things (forecasting), he creates different racks to keep different goods to access them easily and very quickly. He should know where he stored the goods and how they are related say for an example. He would store all the Groceries in one rack, Home Maintenance goods in one rack, canned foods in one rack etc., if he stores the goods logically and physically he will be able to get to know about the Stock easily.

Basic analysis to be done by the shopkeeper before he decides to setup a warehouse.
How is the Demand and supply in the warehouse? To answer this he needs to answer the following questions.

  • Find out the existing stock of goods
  • Does he need new goods                                            – Inserting  new records in Data warehouse
  • Does he need more number of existing goods  -Updating of records in Data warehouse
  • Does he need to remove goods which or not in demand  – Deleting of records in Data warehouse

If a small provisional store needs to decide the progress based on the available data we can imagine the power of data in any big organization. 10 years ago the cost of a 500 MB USB Drive was sold for INR 2500.00, but now we can get 500 GB Flash Drive for INR 2500.00

Image

As on today we have 7,195,883,823 population in this world. Most of them are connected with one or more Public or Private organization , it could be Banks, Schools, Colleges, Employees, Employers etc.,. Like the above shop keeper the organization needs to maintain the Data relates to 7,195,883,823 people. So Experts in Information and Technology industries are developing robust techniques to maintain and validate the data.

Just think 10 years ago the cost of a 500 MB USB Drive was sold for INR 2500.00, but now we are getting 500 GB Flash Drive for INR 2500.00 – what does it mean ? the data is increased !! so we need more space for lesser price !!!

All organizations are very much interested on Customer data to enhance and forecast their business. So they are seeking Information and Technology specialists for designing. Technology specialist are proposing solutions at various levels to capture and maintain the data for Analysis and Forecasting.

Image

In today’s world, all of us are connected through internet be it social networking, ecommerce, online banking etc. So the experts in Information and Technology industries are developing robust techniques to maintain and validate such huge data and assist the businesses to completely change the way they have been working.

Just like analysis of Warehouse data and the trends of customer’s buying trends help a shopkeeper to plan his strategy to buy goods to maximize the profits, any organization needs to analyze the data of its own organization (Internal data about various departments and people in the organization) and the Customer data to forecast its business and strategize to maximize profits. So they are seeking Information and Technology specialists’ expertise for designing a data warehouse. Technology specialists are proposing solutions at various levels to capture and maintain the data for Analysis and Forecasting.

This gave birth to a closed group called Business Intelligence (Group Information System). There are many roles involved to capture the customer data. Let’s discuss responsibilities of few of them.

  1. Solution Architect who designs the whole System right from
    1. How the data is retrieved from source?
    2. How the retrieved data is loaded into Warehouse?
    3. How the data is used for analytic purposes?
  1. Business Analysts who
    1. Analyze the business needs
    2. Create the rules for capturing the right data from the source systems.

3.  Data Analysts who design how the source system and target (warehouse) interact with each other.

  1. What data can be loaded?
  2. How should it be sent into the data warehouse?

4. Developers who convert business needs into coding that will

a. Extract the data from the source system

b. Load the data into warehouse based on the Rules provided by Data    modelers and business analysts

  1. Testers who validate

a. whether source is sending the data what they agreed.

b. Validating the data received based on the business needs

c. Validating the transformation rules defined by the business analysts in Source to target document

d. Validating the code developed by developers are as per the business / transformation rules provided.

Folks – please comment how useful the write up is!!! I will be posting about Test Planning (Estimation,Test Plan, Test Cases and Test Conditions) in my next blog.

Many Thanks – Asik

This post is updated  with the valuable inputs of  Harika Dommeti (Thanks :-))