Type annotations

Type annotations allow you to customize the structs that Cornucopia generates for your rows (and parameters, see the section below). Furthermore, this allows you to share these types between multiple queries.

To create type annotations, declare them using the --: syntax. Type annotations only need to declare the nullable columns. Here's how it looks:

--: Author(age?)

--! authors : Author
SELECT name, age FROM Authors;

--! authors_from_country (country?) : Author
SELECT name, age
FROM Authors
WHERE Authors.nationality = :country;

This will define a struct named Author containing typed fields for the name and age columns (with age being nullable). The same struct will be used for the authors and authors_from_country queries.

Inline types

You can also define type inline if you don't plan on reusing them across multiple queries:

--! authors_from_country (country?) : Author()
SELECT id, name, age 
FROM Authors 
WHERE Authors.nationality = :country;

Notice how inline types must have a set of parenthesis describing their nullable columns. This syntax is often more compact for simple cases. It doesn't have any other special meaning otherwise.

Parameter structs

Cornucopia will automatically generate a parameter struct if it has more than one column. The name of the parameter struct is based on the name of the query. You can still manually generate a parameter struct using a type annotation or an inline type.

In any case, note that you don't need a parameter struct, you can always work directly with the query function (see the section query usage).