ETL: data collection, preparation and transfer to a target system
ETL (English: Extract, Transform, Load) is a data processing process in which information is taken from one or more sources, organised according to set rules and loaded into another system. In English, this process is usually described as extraction, transformation and loading. ETL is especially important when an organisation uses several different systems but wants to present data in a consistent, accurate and reliable way.
In the public sector, ETL solutions are often used in the digital systems of municipalities, schools, libraries, museums and other organisations. For example, information may be taken from a document management system, registers, internal databases or an old website, then adapted to the structure of the new system and automatically transferred to where it is needed. This helps reduce the amount of manual work, avoid errors and ensure that the information provided to residents or staff is consistent.
How does the ETL process work?
ETL has three main stages. Although the principle itself seems simple, in practice each step requires clear rules, data quality control and compatibility between systems.
- Extract – data extraction. In this stage, data are collected from different sources: an old website, Excel files, registers, HR or document management systems, library catalogues or other information systems. In public-sector organisations this is especially relevant because data are often stored in more than one place and different departments use different tools.
- Transform – data transformation. The collected data are cleaned, standardised and adapted to the new format. For example, date formats may be standardised, duplicate records removed, categories corrected, field names changed or the content structure updated to match the requirements of the new website.
- Load – data loading. The prepared data are transferred to the target system – a new website, data store, reporting platform or another solution. At this stage it is important to ensure that the data are loaded accurately, without affecting the system logic, and that users see up-to-date and correct information.
Where is ETL used on public-sector websites?
ETL processes often remain invisible to the end user, but they are an important part of a smoothly running website or digital service. This is especially relevant when an institution aims to centralise information and reduce manual data administration.
- Content migration from an old website. When creating a new municipality, school or museum website, it is often necessary to transfer a large amount of news, pages, documents, events or staff contact details. ETL makes this possible systematically, preserving the content structure and reducing the risk of losing important information.
- Combining data from several sources. Organisations often want to display in one place information coming from different systems – for example, an events calendar, public procurement data, lists of documents or library catalogue information. ETL helps standardise this data and present it clearly to both staff and residents.
- Preparing reports. When management or administration needs consolidated information, the ETL process can collect data from several sources and prepare them for analysis. This is useful when planning services, assessing performance indicators or preparing publicly published reports.
- Regular synchronisation. Some websites or portals have constantly updated information, for example staff contact details, service descriptions, document registers or event lists. ETL makes it possible to automate this process so that data are updated regularly and without additional manual entry.
Why is ETL important for the public sector?
For public-sector organisations, it is important not only to have data, but also to ensure their quality, accuracy and reliable presentation. ETL processes help reduce the number of situations where the same information differs between systems or becomes out of date. This is especially important when residents rely on information published on the website when making decisions or using services.
In addition, ETL helps manage internal processes more efficiently. When data are transferred automatically, staff do not need to enter them manually into different systems several times. This saves time, reduces the administrative burden and allows more attention to be paid to service quality.
ETL and GDPR, security and compliance
If personal data are processed in the ETL process, compliance with GDPR requirements must be ensured. This means that it must be clearly defined which data are transferred, for what purpose they are used, who has access to them and how long they are stored. In practice, it is important to apply the data minimisation principle – transfer only what is actually needed for a specific function or service.
Technical security is no less important. ETL processes should be carried out through secure channels, with clear access management, activity logging and error monitoring. If data are published on a website, it is necessary to ensure that excessive or restricted-use information is not published by mistake.
It is also worth considering the accessibility aspect. Although ETL usually works “behind the scenes”, it determines whether the data presented on the website will be tidy, consistent and properly displayed for different users. For example, correctly uploaded document titles, clear categories, tidy field names and structured content contribute to a better user experience and easier access to information.
When is it worth planning an ETL solution?
ETL is worth planning when an organisation is changing its website, implementing a new portal, connecting several systems or wants to automate repeated data update processes. It is especially useful for projects with a lot of historical content, different data sources or a need to update information regularly.
A well-planned ETL process helps ensure a smooth transition to new digital solutions. For public-sector organisations, this means not only technical convenience, but also more reliable information management, better service delivery and a lower risk of errors in day-to-day work.