When we link to models in sequelize, they are paris of source and target models.

What’s the difference between Has One and Belongs To? Let’s use our User and Post example from earlier to see the difference. This creates an association in which the foreign key for the relationship exists on the target model, thus establishing a one-to-one relationship. The second type of association is the has one association. By default, the target key for a belongsTo relation will be the target model’s primary key. Target keysĪ target key is the column on the target model that the foreign key column on the source model points to. An example of this would be our comment being part of a post, where the foreign key would be on the comment.īy default the foreign key for a belongsTo relation will be generated from the target model name and the target primary key name. The BelongsTo associations are ones where the foreign key for the one to one relation exists on the source model. Here, two models are connected by a single foreign key. The first type of association is one to one associations. This is the same as saying that the user model (the model that the function is being invoked on) is the source and that the comment model (the model being passed as an argument) is the target. For example, in sequelize, you might call a method such as user.hasone(comment). If you’ve set up your databases on and then use sequelize to migrate your databases, you can create these associations there. Target key: a database column that a foreign key references.

Target model: the model to which an association is being defined.įoreign key: a database column that contains references to another table. Source model: the model defining an association. To better understand this concept, let’s go over a few terms.Īssociations: relationships between models. As you can see, simply adding a user_id to a comments or post table would allow us to associate a comment or post with another user.

Postico create primary key