HasOne

HasOne

Represents a one-to-one relationship where the parent model has one related model. The foreign key is stored on the related model's table.

addConstraints

Adds constraints to the relationship query. Filters the related model by the foreign key matching the parent's local key.

Parameters

Name	Description
query	Query builder to add constraints to

Example

// For User hasOne Profile relationship
// Adds: WHERE profiles.user_id = ?

returns — Modified query builder with relationship constraints

getResults

Gets the relationship results. Returns a single related model instance or null if none exists.

returns — Promise resolving to related model or null

create

Creates a new related model and associates it with the parent. Sets the foreign key on the new model to link it to the parent.

Parameters

Name	Description
attributes	Attributes for the new related model

Example

const user = await User.find(1);
const profile = await user.profileRelation().create({
  bio: 'Full-stack developer',
  website: 'https://example.com',
  location: 'San Francisco'
});

console.log(profile.user_id); // Will be set to user.id

returns — Promise resolving to the created model

save

Saves an existing related model and associates it with the parent. Updates the foreign key on the model to link it to the parent.

Parameters

Name	Description
model	Related model instance to save

Example

const user = await User.find(1);
const profile = new Profile();
profile.bio = 'New bio';

await user.profileRelation().save(profile);
console.log(profile.user_id); // Will be set to user.id

returns — Promise resolving to the saved model

associate

Associates an existing model with the parent without saving. Sets the foreign key on the model but doesn't persist the change.

Parameters

Name	Description
model	Related model instance to associate

Example

const user = await User.find(1);
const profile = await Profile.find(5);

user.profileRelation().associate(profile);
console.log(profile.user_id); // Will be set to user.id

// Remember to save the profile to persist the association
await profile.save();

returns — The associated model

dissociate

Dissociates the related model from the parent. Sets the foreign key to null and saves the change.

returns — Promise that resolves when dissociation is complete