Zero to Many, Zero to 1

[Tommy]

Hi was Zero consider in DBML syntax for relationships?
(0-M, 0-1)

Could this be added? perhaps it could be defined like
table1.key 0< table2.key
or
table1.key 0- table2.key
?

[Thi_Nguyen]

Update March 2025: This feature was recently released. You can now test it by defining a relationship with and without nullability for the foreign key. For instance:

Table follows {
  following_user_id int [ref: > users.id] // optional relationship
  followed_user_id int [ref: > users.id, null] // optional relationship
}

Table posts {
  id int [pk]
  user_id int [ref: > users.id, not null] // mandatory relationship
}

Table users { 
  id int [pk]
}

The outcome will be as follows:

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[huydna]

Hi @Tommy, Optional refs have been fully supported with a syntax to denote in dbml version 9.0.0. You can check the doc here: DBML Syntax — Core Database Markup | DBML

A glance of the syntax:

Table users {
  id int [pk]
}

Table profiles {
  id int [pk]
  uid int [unique]
}

Ref: users.id ?-? profiles.id // users can have a profile or not, a profile can belong to a user or not