hasMany

hasMany

Is a many to many relationship (includes join table).
Eg: Patient.hasMany('doctors', Doctor, { why: String }, { reverse: 'patients', key: true }).
Patient can have many different doctors. Each doctor can have many different patients.

This will create a join table patient_doctors when you call Patient.sync():

column name	type
patient_id	Integer
doctor_id	Integer
why	varchar(255)

The following functions will be available:

// Get the list of associated doctors
patient.getDoctors(function(err, doctors) {
  // ...
});

// Add entries to the join table
patient.addDoctors([phil, bob], function(err) {
  // ...
});

// Remove existing entries in join table and add new ones
patient.setDoctors([phil, nephewOfBob], function(err) {
  // ...
});

// Checks if patient is associated to specified doctors
patient.hasDoctors([bob], function(err, patientHasBobAsADoctor) {
  // because that is a totally legit and descriptive variable name
  if (patientHasBobAsADoctor) {
    // ...
  } else {
    // ...
  }
});

// Remove specific entries from the join table
patient.removeDoctors([bob], function(err) {
  // ...
});

// And all of the doctor's have their own methods for selecting patients!
bob.getPatients(function(err, patients) {
  if (patients.indexOf(you) !== -1) {
    // woot!
  } else {
    // ...
  }
});

// and so on and so forth

To associate a doctor to a patient:

patient.addDoctor(surgeon, {why: 'remove appendix'}, function(err) {
  // ...
});

// or...
surgeon.addPatient(patient, {why: 'remove appendix'}, function(err) {
  // ...
});

which will add {patient_id: 4, doctor_id: 6, why: "remove appendix"} to the join table.

API

Model.hasMany(
  name,       // String. Association name
  otherModel, // Model. The model we're association to
  extraProps, // Object. Extra properties that will appear on the join table
  opts        // Object. Options for the association
);

opts

option name	type	description
autoFetch	Boolean	Default: false. If true, association will be automatically fetched with parent.
autoFetchLimit	Number	Default: 1. How many levels deep to auto fetch
key	Boolean	Default: false (for historical reasons). If true, foreign key columns in the table will form a composite key.
mergeTable	String	Custom name for the merge table
mergeId	String	Custom name for column referencing this model
mergeAssocId	String	Custom name for column referencing other model
reverse	String	Default: false. If true, association will be accessible from the other model with the specified name.
getAccessor	String	Default: 'get' + Name. Allows overwriting associating accessor.
setAccessor	String	Default: 'set' + Name. Allows overwriting associating accessor.
hasAccessor	String	Default: 'has' + Name. Allows overwriting associating accessor.
delAccessor	String	Default: 'del' + Name. Allows overwriting associating accessor.
addAccessor	String	Default: 'add' + Name. Allows overwriting associating accessor.