Annotations are named values associated with schema items and
are designed to hold arbitrary schema-level metadata represented as a
str.
There are a number of annotations defined in the standard library. The following are the annotations which can be set on any schema item:
title
description
deprecated
For example, consider the following declaration:
type Status {
annotation title := 'Activity status';
annotation description := 'All possible user activities';
required name: str {
constraint exclusive
}
}The deprecated annotation is used to mark deprecated items (e.g.
str_rpad()) and to provide some information such as what
should be used instead.
To declare a custom annotation type beyond the three built-ins, add an abstract annotation type to your schema. A custom annotation could be used to attach arbitrary JSON-encoded data to your schema—potentially useful for introspection and code generation.
abstract annotation admin_note;
type Status {
annotation admin_note := 'system-critical';
}