A software engineer has recently sparked interest in the tech community by publishing a successful implementation of a neural network built entirely in SQL. This unique project utilizes the xarray-sql library to train and run inference on the classic MNIST handwritten digit dataset directly inside a database environment.
Detailed Developments
The project was shared on GitHub and quickly caught the attention of the Hacker News community in July 2026. The author leveraged basic linear algebra operations to construct the neural network structure without relying on specialized Python machine learning libraries like PyTorch or TensorFlow. The entire forward propagation and backpropagation logic was written in SQL code, allowing computations directly on existing database tables.
Technical & Technology Analysis
The system's architecture relies on the xarray-sql library to map n-dimensional arrays into relational database table structures. Core neural network operations, including matrix multiplication, bias addition, and the ReLU activation function, were translated into complex SELECT, JOIN, and GROUP BY statements. The weight update process via gradient descent was also executed using sequential data update queries, turning a static query tool into a dynamic computational engine.
Expert Opinions & Remarks
Although SQL's training performance certainly cannot match specialized hardware like GPUs or TPUs, the engineering community praises this as an excellent demonstration of advanced algorithmic thinking. Many believe this project blurs the line between data storage and direct data processing, offering a fresh perspective on optimizing large-scale data analytics without the need for data movement.
Impact & Future
This experiment showcases the potential of database management systems equipped with built-in intelligent capabilities (in-database analytics). While not yet applicable to modern large language models (LLMs) due to performance constraints, this approach paves the way for embedding small predictive models and complex data preprocessing tasks directly into enterprise database systems in the future.