Updated June 8, 2023
Introduction to ETL Testing
ETL Testing is performed during the ETL phase, which includes verification and validation of the process of Extracting the data from multiple data sources, transforming all the data to a single common format, and loading the formatted data to the destination. Testers execute ETL Testing through various stages like any other type of testing. The Testing stages are ‘detecting the data sources and analyzing the requirements’, ‘fetching the data and designing the ETL flow’, ‘enforcing the finalized design and database representation’, ‘construction of database/ table and placement of data’, and finally ‘generation of analytical results and reports as per the requirement specification.
Understanding What is ETL Testing?
Extracting means fetching the data from any transactional system or other RDBMS like Oracle, Microsoft, etc. The data in this stage are unstructured and are a huge lump with no meaning. Transform means to sort data or filter out data with the help of operations that are suitable as per the circumstances. Load means transforming data by moving it to a central repository or an OLAP data warehouse.
How does ETL work so Easy?
Let’s take a real-time scenario to explain how ETL works. We know data is everywhere, no matter how smaller the organizations are. The data comes from these resources like staff, employees, work they do in an organization’s business, and several other ways. Since every organization wants to study how their business works and to do this, the best way is to analyze past or historical data. Here comes the ETL concept at the rescue.
E.g., Let us take Organization A has several departments like sales, HR, Development, business, etc. All of these departments have different databases. If Org A wants to analyze data and generate the report, it has to extract the data and transform it into a warehouse to save it for the later stage of analytical work. BI tools will later manipulate this data to provide meaningful insights.
What can you do with ETL Testing?
This one-way process mainly organizes itself for data extraction purposes only. Once the data is fetched out, you can use various tools to manipulate it. We want to inform our readers not to confuse themselves with data warehouse and database testing. The latter concept deal with huge chunks of data compared to its predecessor.
Working with ETL
Working with ETL is not the stuff we want to say to our readers.
An ETL tool has 3 layered architectures built into it.
- Staging Layer: In this layer, the data are accumulated in one place. The data may come from different sources or data systems.
- Data Integration Layer: This layer moves the data to the database it receives from the staging layer. The system sorts the data into hierarchical groups, dimensions, and facts. A combination of facts and dimensions is known as a Schema.
- Access Layer: End-users mainly use this for the final retrieval of data for analytical reporting and information.
Advantages of ETL Testing
Below are the advantages mentioned:
- Visual flow: All the ETL tools can show users a visual flow of the process. This makes the migration process more transparent, and a user learns exactly what is happening. They also generate Scripts IDE.
- Choice of programming code: All the ETL tools allow users to manipulate the work using most programming languages. These are used to write codes. You have to check the language compatibility of the ETL tool you seek.
- Module: Most ETL tools have a module-wise categorization for the dashboard. Each module has a specific purpose. This gives a good user experience with an interactive experience.
- Performance: The test modules give the work done efficiently in the least time possible.
- Easy understanding and maintenance: It has a click and drags functionality to achieve most tasks. Visual appearance gives a better understanding.
Again, no specific knowledge is required to begin your career in ETL testing. We have listed some best-to-have practices for our readers and freshers looking to build their careers in ETL.
- Prefer to have a B.Tech degree in any stream (CSC and IT are preferred).
- Look to have a Master’s degree in a bachelor’s degree in computers.
- Database knowledge is a must; saying this, we would also like to say SQL server knowledge is mandatory.
- Try to have an overview understanding of some BI tools like Tableau and Excel.
Why Use ETL Testing?
To perform data warehouse testing and also for unit testing. To dig deep into our unorganized data. These data can be in multiple forms, from spreadsheets to logs to code data.
To be fair to our readers, we would like to say that ETL is crucial for any company, but the scope depends on availability. Also, it is not developer work, so the demand will not be that demand. With new BI tools and processes, there are alternate ways to dig deep into your dataset. These factors have influenced the scope of ETL testers and tools.
How will this Technology help in Career Growth?
Experience and multiple skills knowledge is something we would recommend to our readers looking to have an ETL career. Please acquire more knowledge as it will be the best survival technique in IT, where things change with every passing date.
Let us see some salary stats the industry is offering to its employees.
- Data Engineer – $66,228
- BI Intelligence – $52,381
- Senior Data Engineer – $78,000
There is a need for ETL testers, and they will always be. However, the concerns are the volume of jobs this technology generates, with the arrival of new technologies and a race to acquire the market by providing multiple features in one product. We want our readers to dig deep and check every possibility. We are only concerned about the volume of jobs in the market worldwide.
This has been a guide to What is ETL Testing? Here we discussed the introduction, working, skills, career growth, and advantages of ETL Testing. You can also go through our other suggested articles to learn more –