The post highlights the importance of relational data modeling with foreign keys in business-critical applications and provides a complete working example using YugabyteDB's YSQL API. Foreign keys enforce referential integrity constraints, which are essential for a relational database design. The implementation of primary and foreign key constraints is a technical challenge in a distributed SQL database due to the need to ensure low latency and high throughput while spanning multiple table shards across different nodes in the cluster. YugabyteDB 2.0 delivers production readiness for YSQL, supporting foreign key constraints and enabling developers to build scalable and maintainable applications without compromising data integrity. The post also discusses the challenges of enforcing foreign key constraints in a distributed SQL database and how YugabyteDB has addressed this issue with its support for serializable transactions since Version 1.2.0 and now also supports snapshot transactions from Version 2.0.3.