A Winning Approach to ETL Testing in Data Warehousing
As data continues to maintain a status quo of being a crucial operational factor in business, data warehousing remains a subject of high priority for enterprises. Today, organizations are better aware of the advantages they can derive from data-driven decision-making. And as a primary aspect of an efficient data warehouse system, ETL (Extract-Transform-Load Testing), by default, emerges as a decisive element.
ETL in data warehousing is important because it is the process that extracts, transforms, cleanses, and loads data from source systems during normal operation without harming the overall performance, reliability, or scalability. For organizations that want to ride on data, ETL testing is a key prerequisite. That is because ETL testing enables users to test the ETL process inside-out, ensuring effective management of data in the Data Warehouse.
| As per a survey, 97 % of enterprises want to accelerate their data transformation process. For them, the time spent on data preparation is the biggest barrier to insights-driven decision-making. |
The Importance of ETL Testing
Spot Problems with the Source Information
Since the ETL process can be tested at an early stage as data gets extracted from source systems, it is possible for testers to identify issues with source information from the very beginning, much before stacking the data in the repository. Furthermore, testers can also identify ambiguities and discrepancies in business rules designed by the organization for managing data transformation and integration.
Easy Transfer of Bulk Data
Testing becomes even more critical in Data Warehousing projects that involve the transfer of bulk data. This is particularly true of large organizations that frequently execute data integration and migration that require the shifting of data from one location to another. ETL testing helps the team to ensure that the data gets transferred completely and safely to the new destination.
Also Read: All that You Need to Know about User Acceptance Testing
Prevent Record Duplication and Data Loss
As an effective method for validating and authenticating information stored in data warehouse systems, ETL is used to prevent the loss and duplication of data. With ETL testing in place, it is easy to ensure that the transfer of data from independent sources is carried out in compliance with the standard and prevailing data transformation rules and that the process is consistent with the data validity tests.
An Ideal ETL Testing Process
ETL testing concepts help ensure the accuracy of data that are moved from the source to the destination. The data is verified in several intermediate steps between the source and the destination. A standard ETL testing process can be divided into eight stages.
| The Global ETL Testing Market is growing rapidly with massive growth rates over the past few years. The market is expected to keep growing significantly from the year 2020 to 2027. |
Identification of Business Requirements
The first step to ETL testing is to create a data model, lay out a business flow, and evaluate the reporting needs of the organization based on its business nature. This step makes it possible for the testers to determine, document, and completely recognize the scope of the project.
Verification of Data Sources
The next step is a data count check for confirming that the table and column data types fulfil the data model specifications. It is vital to ensure that the check keys are set up and that duplicate data is excluded, otherwise, the report could be incorrect or deceptive.
Designing Test Cases and Test Data
In this step, ETL test mapping scenarios are designed, SQL scripts are generated, and multiple rules are described. The mapping document is verified and confirmed in order to ensure that it contains all relevant and valid information.
Data Extraction
ETL tests are implemented based on the market requirements. Here the testers must recognize all kinds of bugs or defects present in the data and prepare a proper report on it. They must ensure to report all flaws, get the bugs solved, and close the bug report before moving ahead.
Testing Data Transformation
This step strengthens object mapping in the source and target systems. It includes examining the data functionality in the target system.
Report Summarization
Report generation is needed for data validation. Report summarizing is the final output of a data warehouse system. The reports produced are tested depending on their layout, filter, options, and calculated values with export functionality.
Test Closure
This final step involves the closure of the file test.
Outsourcing ETL Testing for Optimum Outcomes
Owing to the significance and multiple steps of ETL testing, most organizations prefer to delegate the task to an expert ETL testing services provider specializing in data management services. This enables the client organization to save substantial time and money while ensuring complete data accuracy and safety. Below is a list of a few of the testing services that can be outsourced.
Source to Target Testing
This testing is done to check if the data values transformed are also the expected data values. The service provider firm ensures full data compatibility and eliminates all risks of data loss.
Production Validation Testing
Through this testing, the service provider ensures that no data compromises the integrity of the production system. This test is carried out on data while it is being transferred to the production systems.
Data Completeness Testing
All competent ETL testing service providers offer comprehensive data completeness testing services to their clients. Data completeness testing aggregates the actual data between the source and target for columns with simple to no transformation.
Metadata Testing
Metadata testing includes data length checks, index/constraint checks, and testing of data types, enabling the organization to maintain steady control over its overall information systems. This is because a metadata repository with information about the source, target, mappings, etc. is critical in ETL.
ETL testing is an important part of the data management regime of today’s businesses, particularly the ones dealing with historical data pertaining to finance, travel, etc. When implementing an ETL system for business intelligence, there is an unignorable risk in rushing a data warehouse to service before testing it thoroughly. By delegating the ETL job to a trusted firm, the organization can ensure systematic testing of all its systems and data for bugs, errors, and vulnerabilities before it is integrated and made available.
Who We Are and What Makes Us an ETL Testing Expert?
getSmartcoders has been providing ETL and software testing services to businesses for over a decade now. Our seasoned team of ETL experts and the best-in-class software infrastructure enable us to grasp the dynamics of different business models and create a custom approach to deliver our ETL testing services based on the client’s needs and requirements. We ensure complete adherence to quality standards and can even provide independent validation of the ETL if the client demands it.