ETL Developer Role Explained: Responsibilities, Skills, and When to Hire One?

MARYNA DEMCHENKO

Published: 21 Nov 2020

Data science

Data is the new frontier for companies ever since data has been called the new oil. 

The roles of BI engineers, data scientists, and data analysts have become an integral part of any organization that practices Business Intelligence (BI). In their line of work, data professionals aim to bring value by gleaning useful insights from data. But data needs to undergo a preparation step before the data team can use it. That is where ETL experts step in. 

ETL is the process of transforming raw data so it can be used to gain actionable insights. This article takes a close look at the ETL professional role, including skillsets, responsibilities, and when you're better off adding an ETL developer to your team.

What is ETL?

The abbreviation refers to Extracting, Transforming, and Loading data. An ETL developer designs, develops, and maintains data storage systems and ensures they contain business-relevant data. ETL is a three-fold process and includes the following components.

ETL Procedures in Data Engineering

ETL steps

Extraction. Businesses generate massive volumes of data. It is stored across multiple systems and in diverse formats. Data needs to travel freely between the systems to power your data strategy. Extraction means consolidation of data in required sources like cloud environments, CRM, or external systems. ETL developers use ETL tools to automate this process. 

Transformation. This step is about structuring and formatting data. After data is collected from its sources, it's in a raw state. It needs to transform to be compatible with the defined standards. Thus, this step includes the following steps:

  • Cleansing: removing inconsistencies and missing values. 
  • Standardization: bringing datasets into a required format.
  • Deduplication: excluding irrelevant data.
  • Verification: removing data that can't be used and marking aberrations.
  • Sorting: organizing data by type.

Loading. The final step is loading the transformed data into a database called the Data Warehouse system. Sometimes loading can be frequent, and sometimes it is done at regular intervals. Unlike a typical database, Data Warehouse includes tools to make it accessible for users. These are Business Intelligence tools that let you visualize and report data. 

What do ETL developers do?

Generally, ETL developers design, develop, automate, and support complex applications to extract, transform, and load data. To be more exact, the duties of ETL developers are as follows: 

  • Identifying data storage requirements. ETL developers determine the storage needs of the company. They need a bird's eye view of the data situation to choose the best suiting option. 
  • Building a Data Warehouse. After figuring out the needs, the ETL developers build a data warehouse tailored to an organization's needs.
  • Building reliable data pipelines: a sum of tools and processes that bring data to the user. Pipelines connect data between systems and transfer it from one format into another. 
  • ETL processes. Once the data warehouse is complete, the ETL developer extracts the data and delivers it to the new system. 
  • Quality Assurance. After the warehouse gets off the ground, the ETL developers run tests to ensure its stability. 
  • Debugging. ETL developers rectify all problems with the warehousing system. 

ETL developer: Skillset

An ETL developer is a role that requires expertise in several fields, such as being well-versed in software engineering and database development. To be more specific, this role requires several concrete skills. Here's a list of crucial ETL skills. 

  • The ETL Toolbox

ETL tools are the ready-made solutions that can perform ETL steps right from the start and move data between the sources. The industry standards are Informatica, Talend, and Pentaho. An ETL developer administers the integration of tools with other instruments and implements an interface to ensure data is usable.

  • SQL

ETL processes rely on SQL since it's the most common database language and is used at every stage of the ETL process. In fact, ETL tools are intrinsically SQL generators, so it's vital to have both of those skills. 

  •  Scripting language knowledge 

Sometimes ETL tools aren't enough to cope with all of the requirements. When that happens, ETL developers have to do the heavy lifting with the systems they are working with. Thus, knowledge of a scripting language helps ETL specialists deal with files, users, permission issues, and more. 

  • Data modeling

An ETL developer defines the data formats, the way data will represent in the warehousing system. These are called data models. Reading, analyzing, and transforming data are the key skills that enable an ETL developer to determine data output formats in a database. Those data models define the tools required for transformation. 

  • Database engineering

Database engineers usually create databases, but ETL engineers are also expected to have a background in data mapping and SQL databases to oversee the development process. Additionally, they need to have a solid knowledge of data warehouse architecture's concepts, components, and techniques. 

  • High levels of self-organization

The day of an ETL developer can be pretty intensive, filled with various tasks from business, team management, and tech fields. That's why it's crucial to master time-management skills to fare well in this role. 

When do you need an ETL expert?

An ETL expert will be a part of your data team. The main reason to hire such a team is running a complex, large-scale data system. Here's when you should consider adding an ETL expert to your team:

  • Your business generates more and more varied, unstructured data;
  • You want to be data-driven and thus need insightful data representation;
  • Your business strategy relies on business intelligence development or machine learning
  • Your data processing system is outdated;
  • You feel like your current data methods could use improvement;

Hiring an ELT developer

An ETL developer is a complex role because it requires not only technical expertise but also business acumen. Many developers tend to focus on the technical side while making the most of data requires excelling at coding, management, and business fronts. You could consider hiring a senior business intelligence developer who will develop, deploy, and maintain BI tools and interfaces. If your project uses only off-the-shelf BI tools and solutions, a business intelligence developer might be the right fit to support your data system.

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