With Great Composition Comes Great Responsibility

Elizabeth Engelman
8th Light

One of Datomic’s defining and most powerful characteristics is its composability. Datomic lets us compose complex queries out of simple, independent pieces of logic, allowing developers to fine-tune their database to be extremely performant for unique use cases. However, this same fine-tuning has gotten teams like mine into trouble when their applications naturally grow and evolve over time. In this talk, I’ll introduce Datomic’s components, and explore some of the problems my team encountered with Datomic’s specificity-such as allowing one customer’s unique data model to affect an entire module of queries. We’ll also address why and how the order of our queries matters, explore effective strategies of using query rules, and see how these two things can lead to reusable code that leverages the power of Datomic’s composability without coupling our query logic too tightly to specific use cases.

Elizabeth Engelman is a Software Crafter at 8th Light who enjoys the collaborative nature of creating software. She was inspired to learn to code after attending a Ruby on Rails workshop for women in Washington DC, and journeyed to Chicago to attend Dev Bootcamp. She loves tinkering her way through problems in iterative ways, whether they’re complex software interactions or finding the best recipe for chocolate chip cookies. When not in front of her laptop, Elizabeth enjoys practicing yoga, making art, hanging out with her cats, and exploring Chicago.