BackboneJS: How to cascade Model#destroy?

Question

I have a relational DB (MySQL) at the backend and cool BackboneJS at the frontend. I have several tables (models in BackboneJS jargon) that are interconnected through foreign keys.

PROBLEM

How do I destroy a specific model, such that destruction cascades to all child models?

EXAMPLE

Consider this quick schema:

PERSON
id
name

PHONE_NUMBER
id
person_id
number

EMAIL_ADDRESS
id
person_id
email

Consider that we have a person "Jack" stored in DB with some phone numbers and email addresses. Also, we have BackboneJS models/collections defined for all of the 3 tables and data is loaded into them. A user on the frontend decides to delete records of Jack with a click.

Now here are a few approaches to delete all records of Jack:

APPROACH#1

Call "destroy" on all models of PhoneNumbers and EmailAddresses related to Jack, then call "destroy" on Jack itself.

Problem(s)

Too many AJAX calls for one action.
User will have to wait for a lot of time. (More dependants, more time)
Deletion will be non-transactional. If user closes the browser during, data will be corrupted.

APPROACH#2

Define foreign key relationships at database level, that ensure cascade deletion of PHONE_NUMBERs and EMAIL_ADDRESSes when a PERSON row is deleted. Then "destroy" BackboneJS model for Jack at frontend.

BackboneJS Models for dependants will never know what happened to their corresponding records in the backend. So they'll remain intact.

APPROACH#3

Create a URL on server side application "/thoroughly-delete-person" (which makes sure to delete a person with all of its dependants) and invoke it from the frontend instead of calling BackboneJS's Model#destroy on Jack.

Same problem as in Approach#2

So seems like there is no perfect solution for this simple problem. Did you face it too? What approach did you take and why was it better?

fbynite fbynite · Accepted Answer · 2013-10-16T04:20:34

I had a similar problem, and I went with approach #2, except with one difference.

If you can, represent Jack as a single Backbone Model that contains phone_number and email_address. You can pass the Jack model to other Backbone Views to share Jack's model data. You can then call destroy on the Jack model.

On the backend I used an on delete cascade, so I could just make a query:

delete from PERSON where id = JACK_ID;

I don't know the syntax for mysql but something like:

 PERSON
  id
  name

 PHONE_NUMBER
  id  references PERSON (id) on delete cascade
  person_id
  number

 EMAIL_ADDRESS
  id  references PERSON (id) on delete cascade
  person_id
  email

I'm not sure how well this will fit with your current problem context, but this is similar to what I did, and it works for me.

BackboneJS: How to cascade Model#destroy?

1 Answers