hasMany vs belongsToMany in laravel 5.x
Stefan Izdrail
Founder & Senior Architect · 2026-06-29
Title: Understanding hasMany and belongsToMany Relationships in Laravel 5.x
In Laravel, Eloquent relationships allow us to easily define, access and manage database connections between entities such as models. Two such relationships include 'hasMany' and 'belongsToMany'. These relationships enable us to efficiently handle the association of multiple records linked together with different types of associations in your application logic.
In Laravel 5.x, the Eloquent relationship for hasMany and belongsToMany have slightly different signatures due to how they store their data. The difference is related to the way these relationships store their associated tables and keys. In both cases, we are dealing with one entity that belongs to many other entities, but this can happen in different scenarios or through various table structures.
Let us first look at an example where a Comment hasMany Roles and Roles haveMany Comments:
```php
class Role extends Eloquent {
public function comments() {
return $this->hasMany('App\Comment', 'comment_key', 'role_key'); // Uses the default table name "comments".
}
}
class Comment extends Eloquent {
public function roles() {
return $this->belongsToMany('App\Role', 'my_custom_join_table', 'comment_key', 'role_key'); // Uses a custom table "my_custom_join_table".
}
}
```
Here, the relationship for Comment and Role is defined using different methods: hasMany for Roles to Comments (stored in the default comments table) and belongsToMany for Comments to Roles (stored in a custom join table). This is primarily due to the database schema design. For instance, if you're storing data in different tables or want to use specific foreign keys, these relationships provide flexibility.
If we want to define the inverse relationship (Comment has many Roles, but store the relation in a non-standard table), it can be accomplished as follows:
```php
class Comment extends Eloquent {
public function roles() {
return $this->hasMany('App\Role', 'comment_key', 'role_key')->usingCustomPivotTable();
}
}
```
In this case, we use the 'usingCustomPivotTable' method to specify that the relationship should be stored in a custom table with the mentioned keys. This effectively connects both entities through a non-standard pivot table while still allowing us to define it as a hasMany relation.
The reason for these differences lies in the implementation details of Laravel Eloquent relationships. They are designed to accommodate various database structures and use cases, offering flexibility and ease of use. Always remember that the relationship method chosen depends on your data schema and how you store the information between entities in your application's backend.
In conclusion, hasMany and belongsToMany relationships have different signatures because they cater to different database scenarios and table setups. When working with custom tables or keys, always use the appropriate Eloquent relationship method to effectively manage data association between models and keep things organized.