The role of the ETL developer is increasing in demand on a global scale, with more and more companies realising they need an ETL software developer on board. With this in mind, candidates looking to move into ETL roles need to know the tools and skills they need to succeed in this field.
What is an ETL job?
ETL is the acronym for Extract, Transform and Load, which are the three main components of database management:
- Extract function – reads the data from a specified source database and then extracts the source from it
- Transform function – works with the processed data either by using lookup tables or rules or combining other data to transform it to its desired format.
- Load function – writes the resulting data into the target database – that may or may not have existed previously
What technical skills does an ETL developer need?
The primary technical skills an ETL developer needs include:
- Knowledge of the main tools – ETL developers need them to help them create mappings more easily. These tools include Informatica, Pentaho and Talend.
- Knowledge of SQL – SQL (Structured Language Query) is the backbone of ETL as it is the most popular database language.
- Knowledge of parameterization – Using parameters to change the aspects of ETL jobs dynamically will save both you and the company you work for a lot of time and money. For example, if you have an ETL parameter suitable for a particular environment, you can directly change the setting of the environment rather than creating various jobs for each situation.
- Knowledge of scripting languages – The most used scripting languages for ETL users include Bash, Perl and Python, which can be useful for knowing when ETL tools cannot complete specific requirements.
- Debugging and problem-solving skills – Perhaps the most important technical data skills that an ETL developer needs.
What does an ETL developer do?
ETL developers are the people who are responsible for the design and creation of the data warehouse and all of the related extraction, transformation and loading of the data within the company. After the main groundwork of the design has been laid down, the ETL developer is responsible for testing the model and ensuring it is running correctly.
ETL developers, therefore, need to be able to read, analyse and transform the data depending on what the company wants to do with it. Therefore, people applying for ETL jobs need a more in-depth understanding of different programming languages than other developers.
What are the most popular ETL tools?
The top 10 ETL tools available in the market today are:
- Clover ETL
- Data Migrator
- InfoSphere Information Server (IBM)
- Informatica
- Pentaho Data Integration
- Oracle Warehouse Builder
- SAS Data Management
- SAP Data Services
- SQL Server Integrated Services
- Talend
What is ETL testing?
Once data is extracted from the OLTP (OpenTelemetry Protocol) database, it is then transformed to match the data warehouse schema and loaded into the data warehouse database. There are also a lot of data warehouses that incorporate data from non-OLTP systems such as legacy systems, spreadsheets and text files.
ETL testing is therefore done to ensure the data has been correctly uploaded from the source file to the database after the transformation stage has been completed. This includes verification of data at various stages of use between the source file and the final destination.
The five main stages of ET testing are:
- Recognition of data sources and specifications
- Data acquisition
- Execution of business logic and dimensional modelling
- Building and populating the data
- Reporting
With years of experience working in the cloud and data sector, our consultants can offer you expert industry knowledge. Contact us to find out how to begin or advance your career in ETL development or to expand your ETL team.
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