Sharding-JDBC Database Sharding Explained

Sharding-JDBC is a lightweight Java framework based on JDBC, designed to support sharding (partitioning) for relational databases. It works by intercepting and parsing SQL queries at the application layer, then routing them to different database instances or tables based on configuration rules, enabling horizontal partitioning and distributed storage of data.

The specific principle is as follows:

1. Configuration of data sharding rules: Set up data sharding rules, including sharding key, sharding algorithm, and sharding quantity when the application starts.
2. SQL parsing: When an application initiates a database operation, Sharding-JDBC will intercept the SQL statement and parse out the value of the sharding key.
3. Routing calculation: Based on the sharding rules and the value of the shard key, determine which database instance or table to route to.
4. Data access: routing SQL statements to the corresponding database instance or table for execution, and then returning the results to the application.

By following the above steps, Sharding-JDBC has implemented data sharding and partitioning, distributing data to different database instances or tables to improve database performance and scalability. In addition, Sharding-JDBC also offers features such as transaction consistency and distributed queries to support complex distributed application scenarios.