ETL testing plays a major role in every organization since it benefits directly with all key business decision. Everyone would like to be a master in their own area, if you would like the same on ETL testing then below points definitely would help.
Increase your Knowledge on schema:
Understand the referential integrity of the database alone with cardinality which would help more in designing SQL queries faster and clear, also would help to identify more scenarios using cardinality.
Project to project the database schema would vary, but we should up to the speed of grasping those.
Do more Data analysis:
Understand the data of each table along with the business rules which would help in identifying different test data.
Understand the data flow and data changes within the database.
Create test Design wisely:
With the use of thorough understanding in schema and data, identify the right test scenarios.
Always have an end to end test scenarios which would ensure the data flow without ant loss.
Improve your SQL skill:
Must have good knowledge in Joins (such that what type join need to be used) and built-in functions (such that what function can be replaced to make the query for better performance).
ETL concepts and process:
Love what you do:
I would say that this would be foremost one for success in any field with high satisfactions if you achieve a big thing without satisfaction then it does not make sense, always have passion about your work if not make yourself by creating more involvement.
Just think a minute, are doing the same work every day? Then think of how can it be automated? For example, you are executing the same flavor of SQL scripts every day or every release, try to develop an automation utility to execute the SQL scripts. Learn any scripting language.
Do you think, tester means doing test design, executing, reporting and tracking defects? No, a tester is no more defect finder, a tester is a defect blocker. We need to stop the defects by identifying those in early stage itself.
Be a part of the project from the beginning, and come up with questionnaires during requirement stage itself.
Say no to open Assumptions:
Never ever assume yourself in anything on data flow, transformation, and schema. Get confirmations from respective team.
Come out of Comfort-zone:
Do you feel that you are in the comfort zone and not learning anything new, then it’s right time about your shift into the task which would challenge your skill or for an innovative approach?
Have a good soft skill to handle different situations with stakeholders.
Never miss to give Feedback:
Always ask yourself where you stand and where you want to be regularly.
Have continuous improvement plan.
Take others feedback as cultivate and act on those.
Have Plan, Act and Review model.
Think about future:
Set long term goal, keep the clear vision and work towards on it. Always ask yourself what next as soon as you complete one activity which makes you become a master in ETL testing.