Details of ETL Testing

Business Intelligence (BI) and data warehouse are two terms quite frequently heard in business discussions. ETL testing is related to these two things and hence you should know more about these two before going into the details of ETL testing.

What is BI?

The process of collecting row business data and converting them to useful and more meaningful information is called as Business Intelligence or BI.  Here the data is in the form of records of the daily transactions such as daily sales records, production details, interactions with customers etc and these can be converted into useful information for facilitating analysis and taking decisions.

What is Data Warehouse?

A Data warehouse is a database designed exclusively for query and analysis rather than transactions. Data from multiple heterogeneous sources will be integrated to create a data warehouse. Data warehouse will help the organizations and companies to aggregate data from different sources onto a single platform and to perform separate analysis from transaction workload. In data warehouse the data will be turned into useful information which can be used for different purposes at different levels.

What is ETL?

ETL is the process of collecting data from different heterogeneous sources and loading the same into the data warehouse. Here the data will be transformed to match the data warehouse schema. The alphabets ETL stands for Extract, Transform and Load.

For example let us take a home appliances manufacturing company. The company has different products and they are selling the products through a network of dealers. The details related to production will be at the production unit and those related to sales will be with the sales department. Customer care department will have the details of the response from the customers. All this data should be brought onto a single platform for analyzing before charting out a new marketing strategy. ETL will be useful here.

What is ETL Testing?

ETL testing is meant for ensuring that the data extracted from different sources and loaded in the warehouse after transformation is accurate. This testing will be executed at different middle points in between the source and the destination.

ETL Testing Process

As in the case of all other testings, ETL testing will be executed through different phases and these phases are

  • Business and requirements understanding
  • Test planning and Estimation
  • Designing test cases and planning test data
  • Test execution with bug reporting and closure
  • Summary report and result analysis
  • Test Closure.

This test will be done in five stages as follows

  1. Identifying data sources and requirements
  2. Data Acquisition
  3. Implement business logics and dimensional modelling
  4. Build and populate data
  5. Build reports

Following are the different types of ETL testing

  • Production Validation Testing
  • Source to Target Testing
  • Application upgrades
  • Metadata Testing
  • Data Completeness Testing
  • Data Accuracy Testing
  • Data Transformation Testing
  • Data Quality Testing
  • Incremental ETL Testing
  • GUI/ Navigation Testing

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