2 posts tagged with "data-access"

Go programmers are comfortable with the comma-ok idiom:

value, ok := lookup(key)

That shape is useful for an E expression too, but one boolean cannot explain why a value is absent. In data-access code, there is a critical difference between a loaded null-like value and a field the query never selected.

TeaQL's generated Go E expressions preserve three states and provide two evaluation styles: TryEval() for explicit error handling and Eval() for strict fail-fast business logic.

Python makes absence easy to express. A database NULL, a missing JSON key, an empty relation, and an optional function result can all become None.

That convenience becomes dangerous for partially loaded entities. If a query did not select task.name, returning None tells business code something the runtime does not know.

TeaQL's generated Python E expressions keep Value, Null, and NotLoaded separate. Loaded nulls evaluate to None; unselected fields raise a structured TeaQLNotLoadedError.