A Pointer is any object that can be referenced by its id.

Pointer is a simple table consisting of three fields:

• id - the database-unique id for this pointer in ULID format.
• table_id - a type tag, references Table.
• deleted_at - timestamp of when the object was deleted, null by default.

To reference any object, simply reference Pointer:

alias Needle.Pointer
belongs_to :object, Pointer

To define a new object type there are two options, you should choose one:

• Virtual - an object type with a view over Pointer limited by type.
• Pointable - an object type with a table which is kept synchronised with Pointer.

For most purposes, you should use a Virtual. Pointable exists mostly to support existing code. The major difference in practice is that you cannot add new fields to a virtual. Most of the time you will want to store such extra fields in one or more mixins anyway so they may be reused.

See Mixin for more information about mixins.