NCS Insights

ETL Process in Qlik: From Data Extraction to Loading

Written by Igor Ribeiro | Aug 28, 2024 2:26:25 PM

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In the world of data analytics, the ability to efficiently process and transform raw data into meaningful insights is critical to maintaining a competitive edge. Businesses today are inundated with data from various sources, ranging from databases and cloud services to APIs and flat files. However, this data is often unstructured, inconsistent, and not immediately ready for analysis. This is where the ETL process (Extract, Transform, Load) becomes indispensable.

This article explores what ETL and ELT are, the roles of QVD and QVF files, and how these elements are organized within Qlik to ensure efficient data management.

What is ETL and ELT?

In data management, ETL (Extract, Transform, Load) and ELT (Extract, Load, Transform) are essential methodologies for preparing data for analysis. While both methods aim to make data ready for reporting and insights, they differ in how and when the data is processed.

ETL is a traditional data processing workflow that involves three main steps:

  • Extraction: The process begins with extracting data from various sources, such as databases, APIs, flat files, or other systems. The goal is to gather the necessary raw data in its original format.
  • Transformation: Once extracted, the data undergoes transformation. This step involves cleaning, filtering, aggregating, and restructuring the data to meet business needs. The transformation process ensures that the data is consistent, accurate, and ready for analysis.
  • Loading: Finally, the transformed data is loaded into a target system, such as a data warehouse, where it can be accessed and used for reporting and analysis.

ELT, on the other hand, slightly alters the sequence. Data is first loaded into the target system in its raw format and then transformed within that system. This approach is often preferred when working with large volumes of data, as it leverages the processing power of modern databases and cloud platforms to perform transformations more efficiently.

QVD and QVF Files: Roles in Qlik's ETL Process

In the Qlik ecosystem, two types of files are essential for data management: QVD and QVF files. These formats play crucial roles in organizing and optimizing the entire process.

  • QVD Files: These are highly optimized storage formats designed for fast data retrieval. When data is extracted from source systems, it is often saved in these files, allowing for quick access and reuse in various applications. This intermediate storage reduces loading times and improves overall efficiency.
  • QVF Files: These contain complete applications, including data models, visualizations, and scripts. While QVDs handle raw and transformed data, QVFs are where this data is loaded for analysis and reporting, serving as the interface through which users interact with the data.

The ETL Process in Qlik: Organizing Apps

The ETL process in Qlik is a meticulously organized workflow that ensures data flows smoothly from raw extraction to final visualization. This process centers on the strategic use of QVD and QVF files at different stages, each playing a crucial role in preparing data for analysis.

Extract Phase: Raw QVD Files

The process begins with the extraction phase, where raw data is pulled from various source systems such as databases, APIs, flat files, and cloud services. A dedicated QVF file is created specifically for this task and connects to the data sources and extracts the data in its original, unaltered form. The extracted data is then saved into QVD files. At this stage, these files store the data exactly as it was retrieved, with no transformations applied, ensuring it is optimized for the subsequent stages of the process.

Transform Phase: Working with QVDs

After extraction, the focus shifts to transforming the data to prepare it for analysis. In this phase, another application reads the raw data files previously created and applies various transformation tasks, such as data cleansing, applying business logic, restructuring, and aggregating data. Once the data has been processed and meets the specific business requirements, it is saved back into new QVD files, now containing cleaned and analysis-ready data.

Load Phase: Visualization and Analysis

The final stage involves loading the transformed data into the platform’s visualization and analysis tools. This is where the data, now in its final form, is used to create models, visualizations, and dashboards. The application responsible for this phase reads the processed data files, without performing any further transformations, and utilizes the data to build fast, responsive visualizations. This structured approach ensures that by the time data reaches this stage, it has been fully optimized for analysis, allowing for efficient querying and insightful decision-making. This structured approach, separating extraction, transformation, and loading into distinct phases with dedicated QVF files, ensures that the ETL process in Qlik is both efficient and effective, providing a reliable foundation for data-driven decision-making.

The ETL process in Qlik is a powerful and organized approach to managing data, ensuring that information flows smoothly from extraction to final analysis. Understanding and implementing this process can greatly improve how your organization handles data, leading to more informed and timely business decisions.

NCS Consulting can help you optimize your data management with Qlik’s ETL process. Contact us today to see how we can enhance your data handling and drive better business outcomes.