Polymorphic relationships in Laravel - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a polymorphic relationship in Laravel?

A polymorphic relationship allows a model to belong to more than one other model on a single association. For example, a Comment model can belong to both a Post and a Video model using the same relationship.

intermediate

How do you define a polymorphic one-to-many relationship in Laravel?

Use the morphMany method on the parent model and morphTo on the child model. For example, a Post model has many comments with comments() using morphMany, and Comment uses commentable() with morphTo.

beginner

What database columns are required for polymorphic relationships?

You need two columns on the related table: <code>{relation}_id</code> and <code>{relation}_type</code>. For example, in comments table, <code>commentable_id</code> stores the ID and <code>commentable_type</code> stores the model class name like 'App\\Models\\Post'.

advanced

Can polymorphic relationships be used with many-to-many relationships in Laravel?

Yes, Laravel supports polymorphic many-to-many relationships using morphToMany and morphedByMany methods. This allows a model to belong to multiple models on a many-to-many basis with a single pivot table.

intermediate

Why use polymorphic relationships instead of multiple foreign keys?

Polymorphic relationships simplify the database design by using one set of columns to relate to multiple models. This avoids adding many nullable foreign keys and makes the code cleaner and easier to maintain.

Which two columns are essential for a polymorphic relationship in Laravel?

A model_id and model_type

B foreign_id and foreign_type

C relation_id and relation_type

D id and type

The columns must be named {relation}_id and {relation}_type, for example commentable_id and commentable_type.

Which method defines the inverse side of a polymorphic one-to-many relationship in Laravel?

A belongsTo

B morphMany

C hasMany

D morphTo

morphTo is used on the child model to define the inverse polymorphic relationship.

What does the morphMany method do in Laravel?

A Defines a polymorphic many-to-many relationship

B Defines a polymorphic one-to-many relationship

C Defines a standard one-to-many relationship

D Defines a belongsTo relationship

morphMany defines a polymorphic one-to-many relationship from the parent model.

Which Laravel method is used for polymorphic many-to-many relationships?

A morphToMany

B morphTo

C morphMany

D belongsToMany

morphToMany is used to define polymorphic many-to-many relationships.

Why might you choose polymorphic relationships in your Laravel app?

A To avoid multiple nullable foreign keys and simplify code

B To increase database size

C To make queries slower

D To avoid using Eloquent models

Polymorphic relationships reduce complexity by using one relation for multiple models, avoiding many nullable foreign keys.

Explain how to set up a polymorphic one-to-many relationship in Laravel with an example.

Think about how comments can belong to posts or videos using the same table.

Describe the benefits of using polymorphic relationships over multiple foreign keys in Laravel.

Consider how many models can share the same related data type.