Schema for Entity with to many attributes to define

Is there a way to define an entity that has an undefined number of attributes and new attributes are added as they come?

Like:

person sub entity
owns atribute 1
owns atribute 2
.
.
.
owns attribute n

//and then define the attributes separately?

attribute1 sub attibute
value double

// and the value of the attribute to be unique to the entity eg a telephone number?

You can update schemas.

If you start with:

attribute_1 sub attribute, value string;
person sub entity, owns attribute_1;

If you want to add an attribute, you don’t need to re-define all of person.
Specifying @key makes the attribute value unique to the entity.

attribute_2 sub attribute, value long;
person owns attribute_2 @key;