role assignment
Role assignment doesn’t use any specific keyword, but it uses parentheses to assign players to roles in a relation.
Syntax
The syntax of a role assignment statement includes:
-
Subject — concept variable
-
Object — parentheses with comma separated list of:
-
role label and concept variable, separated by a colon
-
<concept-variable> ( [<role>:]<concept-variable> [,[<role>:]<concept-variable>] )The role is optional. If no role provided for a player, its role is inferred via its type and schema.
There can be any number of players per role and at least one role specified in a role assignment statement.
Behavior
TypeQL role assignment statements can be used only in data queries and rules.
Since only relations can have roles, the subject concept variable is implicitly bound to the relation type.
You can specify the type of the concept variable by bounding it explicitly with an
isa statement.
Usage in a match pattern
For this example, use a database with the IAM schema and sample data loaded.
For example, let’s find all relations for a user with full-name of Kevin Morrison:
match
$rel ($person) isa! $type;
$person isa person, has full-name "Kevin Morrison";
fetch
$type;See example output
{ "type": { "label": "permission", "root": "relation" } }