How To Use Polymorphic Relationships / Associations!

@Ruffles a two-video series here https://laracasts.com/lessons/build-an-activity-feed-in-laravel

@Ricardo Nope, that's not it. Jeffrey is using normal relationships in these videos.

There's a video from Taylor about it. True, it's quite old, probably a bit outdated too, but it's worth mentioning: https://youtu.be/PzGC4ub6RDg

@Ruffles Are you sure? 100%? Look at 2:43...

@Ricardo yeah, I just checked it and you are right!

@Ruffles no worries :)

I think you should edit your first post and collect there the relevant info, so one no need to search over the whole thread to find the info needed.

Updated my original post with the videos, also I added the Polymorphic Huh? lesson.

I ld love to see some advanced videos on this topic as well. I am familiar with Polymorphism from JAVA and it is, yet another approach to, a good software design. It is actually a fundamental principal of OOP, and I think it is at the heart of Laravel framework itself.

Some theory on it...

Polymorphism provides a means to create elegant versatility in our software. It allows us to apply a consistent approach to inconsistent but related behavior. We should try to find opportunities in our software systems that lend themselves to polymorphic solutions. We should seek them out, actively and deliberately, before we begin to write code. ( Source )

Whenever you find situations in which different types of objects perform the same type of behavior, there is an opportunity for a polymorphic solution. The more experience you get, the easier it will be to detect such situations.

Here are some situations where polymorphic relationships works best:

• All business transactions must be logged. ( loggable )
• A drawing program allows the user to draw various shapes. ( drawable )
• An Object to Array conversion. ( arrayable )

Added 2 blog articles:

• Using Polymorphic Relations in Laravel
• Creating Polymorphic Relations in Laravel 5

As a related topic, currently we try to support new type of relation multi table inheritance.

it is inspired from doctrine 2 Class Table Inheritance.

@ahmed-abu-shaban Cool! Doctrine 2 is a Data Mapper compared to Eloquent which is an Active Record Implementation. Look at Analogue: Eloquent-Like Data Mapper

@Ruffles articles are the same as the video Polymorphic huh

Added a new blog post:

User Types And Polymorphic Relationships

I use them sometimes. Imo it replaces a pivot table, and In some cases multiple pivots.

But the draw back can be coupled code and a huge table that can slow response time considerably. Take for example, though can be crazy, gets my point across.

Your app has a discussion board that users comment on a post. A blog that users can comment on a article. You could just have one comment table that utilizes a polymorphic relationship. But as you could imagine that table and model becomes tightly coupled to both features or a feature as it's self with dependencies. Also imaging who big that table could get.

Now as the docs point out photos, that could also get bloated if not carefully constructed.

Interesting reply, @jekinney ! I've read in another thread (I was asking about pros and cons there) that they might cause performance issues but if the right fields are indexed properly, it won't be that big of a deal! Not really a database and performance pro but I have to investigate this further.

@Ruffles thank you, more personal preference I think then as you stated performance per say. I just imagine then experience that like I sated a comment table could end up with a million rows where the other tables might have a few thousand each.

Added this new video Pushing Polymorphism To The Database to the list of videos.