Introduction

This Laravel Eloquent extension adds support for JSON foreign keys to BelongsTo, HasOne, HasMany, HasOneThrough , HasManyThrough, MorphTo, MorphOne and MorphMany relationships.

It also provides many-to-many and has-many-through relationships with JSON arrays.

Compatibility

Database	Laravel
MySQL 5.7+	5.5.29+
MariaDB 10.2+	5.8+
PostgreSQL 9.3+	5.5.29+
SQLite 3.18+	5.6.35+
SQL Server 2016+	5.6.25+

Installation

composer require "staudenmeir/eloquent-json-relations:^1.1"

Use this command if you are in PowerShell on Windows (e.g. in VS Code):

composer require "staudenmeir/eloquent-json-relations:^^^^1.1"

Usage

• One-To-Many Relationships
  • Referential Integrity
• Many-To-Many Relationships
  • Array of IDs
  • Array of Objects
  • Query Performance
• Has-Many-Through Relationships
• Concatenation

One-To-Many Relationships

In this example, User has a BelongsTo relationship with Locale. There is no dedicated column, but the foreign key (locale_id) is stored as a property in a JSON field (users.options):

class User extends Model
{
    use \Staudenmeir\EloquentJsonRelations\HasJsonRelationships;

    protected $casts = [
        'options' => 'json',
    ];

    public function locale()
    {
        return $this->belongsTo(Locale::class, 'options->locale_id');
    }
}

class Locale extends Model
{
    use \Staudenmeir\EloquentJsonRelations\HasJsonRelationships;

    public function users()
    {
        return $this->hasMany(User::class, 'options->locale_id');
    }
}

Remember to use the HasJsonRelationships trait in both the parent and the related model.

Referential Integrity

On MySQL , MariaDB and SQL Server you can still ensure referential integrity with foreign keys on generated/computed columns.

Laravel migrations support this feature on MySQL/MariaDB:

Schema::create('users', function (Blueprint $table) {
    $table->bigIncrements('id');
    $table->json('options');
    $locale_id = DB::connection()->getQueryGrammar()->wrap('options->locale_id');
    $table->unsignedBigInteger('locale_id')->storedAs($locale_id);
    $table->foreign('locale_id')->references('id')->on('locales');
});

Laravel migrations (5.7.25+) also support this feature on SQL Server:

Schema::create('users', function (Blueprint $table) {
    $table->bigIncrements('id');
    $table->json('options');
    $locale_id = DB::connection()->getQueryGrammar()->wrap('options->locale_id');
    $locale_id = 'CAST('.$locale_id.' AS INT)';
    $table->computed('locale_id', $locale_id)->persisted();
    $table->foreign('locale_id')->references('id')->on('locales');
});

There is a workaround for older versions of Laravel.

Many-To-Many Relationships

The package also introduces two new relationship types: BelongsToJson and HasManyJson

On Laravel 5.6.25+, you can use them to implement many-to-many relationships with JSON arrays.

In this example, User has a BelongsToMany relationship with Role. There is no pivot table, but the foreign keys are stored as an array in a JSON field (users.options):

Array of IDs

By default, the relationship stores pivot records as an array of IDs:

class User extends Model
{
    use \Staudenmeir\EloquentJsonRelations\HasJsonRelationships;

    protected $casts = [
       'options' => 'json',
    ];
    
    public function roles()
    {
        return $this->belongsToJson(Role::class, 'options->role_ids');
    }
}

class Role extends Model
{
    use \Staudenmeir\EloquentJsonRelations\HasJsonRelationships;

    public function users()
    {
       return $this->hasManyJson(User::class, 'options->role_ids');
    }
}

On the side of the BelongsToJson relationship, you can use attach(), detach(), sync() and toggle():

$user = new User;
$user->roles()->attach([1, 2])->save(); // Now: [1, 2]

$user->roles()->detach([2])->save();    // Now: [1]

$user->roles()->sync([1, 3])->save();   // Now: [1, 3]

$user->roles()->toggle([2, 3])->save(); // Now: [1, 2]

Array of Objects

You can also store pivot records as objects with additional attributes:

class User extends Model
{
    use \Staudenmeir\EloquentJsonRelations\HasJsonRelationships;

    protected $casts = [
       'options' => 'json',
    ];
    
    public function roles()
    {
        return $this->belongsToJson(Role::class, 'options->roles[]->role_id');
    }
}

class Role extends Model
{
    use \Staudenmeir\EloquentJsonRelations\HasJsonRelationships;

    public function users()
    {
       return $this->hasManyJson(User::class, 'options->roles[]->role_id');
    }
}

Here, options->roles is the path to the JSON array. role_id is the name of the foreign key property inside the record object:

$user = new User;
$user->roles()->attach([1 => ['active' => true], 2 => ['active' => false]])->save();
// Now: [{"role_id":1,"active":true},{"role_id":2,"active":false}]

$user->roles()->detach([2])->save();
// Now: [{"role_id":1,"active":true}]

$user->roles()->sync([1 => ['active' => false], 3 => ['active' => true]])->save();
// Now: [{"role_id":1,"active":false},{"role_id":3,"active":true}]

$user->roles()->toggle([2 => ['active' => true], 3])->save();
// Now: [{"role_id":1,"active":false},{"role_id":2,"active":true}]

Limitations: On SQLite and SQL Server, these relationships only work partially.

Query Performance

On PostgreSQL, you can improve the query performance with jsonb columns and GIN indexes.

Use this migration when the array of IDs/objects is the column itself (e.g. users.role_ids):

Schema::create('users', function (Blueprint $table) {
    $table->bigIncrements('id');
    $table->jsonb('role_ids');
    $table->index('role_ids')->algorithm('gin');
});

Use this migration when the array is nested inside an object (e.g. users.options->role_ids):

Schema::create('users', function (Blueprint $table) {
    $table->bigIncrements('id');
    $table->jsonb('options');
    $table->rawIndex('("options"->\'role_ids\')', 'users_options_index')->algorithm('gin'); // Laravel 7.10.3+
    //$table->index([DB::raw('("options"->\'role_ids\')')], 'users_options_index', 'gin');  // Laravel < 7.10.3
});

Has-Many-Through Relationships

Similar to Laravel's HasManyThrough, you can define HasManyThroughJson relationships when the JSON column is in the intermediate table (Laravel 9+). This requires staudenmeir/eloquent-has-many-deep.

Consider a relationship between Role and Project through User:

Role → has many JSON → User → has many Project

Install the additional package, add the HasRelationships trait to the parent (first) model and pass the JSON column as a JsonKey object:

class Role extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function projects()
    {
        return $this->hasManyThroughJson(
            Project::class, User::class, new JsonKey('options->role_ids')
        );
    }
}

The reverse relationship would look like this:

class Project extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function roles()
    {
        return $this->hasManyThroughJson(
            Role::class, User::class, 'id', 'id', 'user_id', new JsonKey('options->role_ids')
        );
    }
}

Concatenation

You can include JSON relationships into deep relationships by concatenating them with other relationships using staudenmeir/eloquent-has-many-deep (Laravel 9+).

Consider a relationship between User and Permission through Role:

User → belongs to JSON → Role → has many → Permission

Install the additional package, add the HasRelationships trait to the parent (first) model and define a deep relationship:

class User extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;
    use \Staudenmeir\EloquentJsonRelations\HasJsonRelationships;

    public function permissions()
    {
        return $this->hasManyDeepFromRelations(
            $this->roles(),
            (new Role)->permissions()
        );
    }
    
    public function roles()
    {
        return $this->belongsToJson(Role::class, 'options->role_ids');
    }
}

class Role extends Model
{
    public function permissions()
    {
        return $this->hasMany(Permission::class);
    }
}

$permissions = User::find($id)->permissions;

Contributing

Please see CONTRIBUTING and CODE OF CONDUCT for details.