0οΈβ£ Optional Relationships in DBML
Back in Zero-to-One/Many Relationships we started drawing optional relationships, working it out from the nullable constraint on the foreign key. Now you can say it directly: add a ? to either side of a relationship operator to mark that side optional. It works with all four operators (<, >, -, <>).
Table orders {
id int [pk]
customer_id int [ref: ?> customers.id] // a customer may have no orders
coupon_id int [ref: ?>? coupons.id] // an order may have no coupon
}
New to relationship types, or want to see optional refs across one-to-one, one-to-many and many-to-many with sample data? Read the tutorial on optional relationships.
π Read the full syntax docs β
Give it a try and let us know what you think.
