Attribute Macro database

#[database]

This attribute is placed on your database struct. It takes a list of the query groups that your database supports. The format looks like so:

#[salsa::database(MyQueryGroup1, MyQueryGroup2)]
struct MyDatabase {
    runtime: salsa::Runtime<MyDatabase>, // <-- your database will need this field, too
}

Here, the struct MyDatabase would support the two query groups MyQueryGroup1 and MyQueryGroup2. In addition to the database attribute, the struct needs to have a runtime field (of type salsa::Runtime) and to implement the salsa::Database trait.

See the hello_world example for more details.