Algebraic data types are a common and powerful tool for modeling complex data structures in programming. While you can map some product types to database tables, sum types are more challenging to represent in a relational database. This lack of expression causes impedance mismatches between the application and the database. In this article, we'll explore how sum types can be implemented in ScopeDB using variant data types.

When developing the query language for ScopeDB, we decided to go against SQL and design a new language, ScopeQL, from scratch to fix SQL's problems. In this post, we will discuss where SQL falls short and the design principles behind ScopeQL.