#VDZ26 
At various times over the past 30 years, most relational database platforms have implemented the core components of declarative data integrity - primary keys, uniqueness, check constraints and foreign keys. Whist these remain a critical part of the database, the real-life business rules about your data are much more complex. They can't be implemented with the simple data integrity rules that exist today, and hence modern applications are filled with code to enforce these rules at the application level.

The SQL standard always knew that business rules would be more complex and provided a mechanism called "SQL Assertions" to declaratively enforce complex, cross-table invariants directly in the database. But no database vendor has ever attempted to tackle an implementation of SQL Assertions...until now!

In this session we'll demonstrate a native SQL Assertions implementation. You'll be introduced to SQL assertions, how to manage them, and how they behave compared to the already (traditional) available constraints.

Devoxx

A conference talk by an Oracle developer arguing that virtually every database contains corrupt data due to the near-impossibility of enforcing complex multi-row, multi-table business rules through application code. Using live demos, the speaker shows how a seemingly simple rule like 'no employee can earn more than their department head' explodes into hundreds of lines of API code riddled with edge cases and concurrency bugs. The core solution presented is SQL assertions — a feature defined in the 1992 SQL standard but never implemented by any major vendor until Oracle. Assertions let developers declare boolean constraints directly in the database engine, which then handles validation, edge cases, and concurrency automatically. The talk covers deferrable assertions, partial validation, performance characteristics, and current limitations such as no aggregation support and a maximum of three levels of nesting.

Data Integrity 2.0. The biggest advancement in data quality in 30 years! by Connor McDonald