ETL #
Introduction #
ETL, which stands for Extract, Transform, Load, is a key process used in data integration strategies, particularly in the context of building and maintaining data warehouses. The ETL process involves three distinct steps:
1. Extract This is the first stage in which data is collected or extracted from various heterogeneous source systems. These sources can include relational databases, flat files, web APIs, or other forms of data storage. The primary challenge in this step is ensuring the reliable and efficient extraction of data, which may be structured or unstructured, without affecting the source system’s performance.
2. Transform During the transformation phase, extracted data undergoes various operations to prepare it for loading into the target system. This can involve a series of steps such as cleansing (correcting or removing corrupt or inaccurate records), standardizing data formats, enriching data (adding value to the data through amalgamation of data from various sources), deduplicating records, sorting, joining, aggregation, and others. The goal is to convert the raw data into a format that aligns with the business logic of the target system and supports analytics.
3. Load The final step involves loading the transformed data into the destination system, typically a data warehouse, data mart, or a large database. This can be done in a batch process (all at once during off-peak hours) or through a more continuous, incremental process known as streaming. The load process must ensure that the data is loaded efficiently and accurately, and that the process supports the querying and retrieval needs of the end-users.
ETL is a critical component in data management, especially in distributed systems where data consistency, data integration, and efficient data processing are paramount. It not only supports the operational requirements of such systems but also provides the data foundation necessary for advanced analytics and business intelligence operations.
Learning Resources #
Books #
- Understanding ETL
- The Data Warehouse ETL Toolkit: Practical Techniques for Extracting, Cleaning, Conforming, and Delivering Data
Courses #
- What is ETL for Beginners | ETL Non-Technical Explanation
- What is ETL | What is Data Warehouse | OLTP vs OLAP
- What Is ETL | Extract Transform And Load Tools | What Is ETL Tools | Intellipaat
- What is ETL with a clear example - Data Engineering Concepts
- What is ETL (Extract, Transform, Load)?