Blueprint foreignIdFor should add foreign key constraint

[tavsec]

Hey!
Recently, I used foreignIdFor() method to create a few migrations. After inspecting the migrated SQL database, I discovered that the generated table does not include foreign keys.
Migration example:

public function up()
{
    Schema::create('products', function (Blueprint $table) {
        $table->id();
        $table->string('name');
        $table->foreignIdFor(\App\Models\Manufacturer::class);
    });
}

will generate the following table (DDL):

create table products
(
    id                         bigint unsigned auto_increment        primary key,
    name                       varchar(255)                          not null,
    manufacturer_id            bigint unsigned                       not null
)

And now I am wondering, what is the benefit of using foreignIdFor() method instead of using unsignedInt() method?
I think it would be a nice addition for foreignIdFor() method to create an actual foreign key constraint, like this:

public function up()
{
    Schema::create('products', function (Blueprint $table) {
        $table->id();
        $table->string('name');
        $table->foreignIdFor(\App\Models\Manufacturer::class)->references("id")->on("manufacturers");
    });
}

which generates the following DDL:

create table products
(
    id                         bigint unsigned auto_increment        primary key,
    name                       varchar(255)                          not null,
    manufacturer_id            bigint unsigned                       not null,
    constraint products_manufacturer_id_foreign
        foreign key (manufacturer_id) references manufacturers (id)
)

Looking forward to your replies!
Have a nice day :)

[anilkumarthakur60]

public function up()
{
    Schema::create('products', function (Blueprint $table) {
        $table->id();
        $table->string('name');
        $table->foreignIdFor(\App\Models\Manufacturer::class)->constrained()
    });
}

just adding constrained method can resolve your problem

[Sophist-UK]

The reason that Laravel doesn't automatically add an SQL constraint is that sometimes you don't want one but you want someone reading the migration code to understand that the field is nonetheless a foreign key.

But there are several methods of adding a constraint in your migration, including the one mentioned by @anilkumarthakur60, the one you mentioned in your original post and the following:

$table->foreign('manufacturer_id')->references('id')->on('manufacturers');

[anilkumarthakur60]

while adding and dropping ...better way to define is to give the name of foreignKey as a second parameter

 public function up(): void
    {
        Schema::table('products', function (Blueprint $table) {
$table->foreign('manufacturer_id','products_manufacture_if_foreign')->references('id')->on('manufacturers');    
    });
    }


    public function down(): void
    {
        Schema::table('products', function (Blueprint $table) {

            $table->dropForeign('products_manufacture_if_foreign');//to drop foreign
        });
    }

[deltour-hugo]

[Sophist-UK]

Because you are doing Schema::create rather than Schema::table - see https://laravel.com/docs/10.x/migrations#updating-tables. Try:

Schema::table('category_post', function (Blueprint $table) {
    $table->foreignIdFor(Category::class)->constrained()->cascadeOnDelete();
    $table->foreignIdFor(Post::class)->constrained()->cascadeOnDelete();
    $table->primary(['category_id', 'post_id']);
});

[Khant-Nyar]

what about this @Sophist-UK
it was completely fine in local but in production get error

Schema::create('cases', function (Blueprint $table): void {
            $table->ulid('id')->primary()->unique()->index();
            $table->integer('case_number')->unique()->comment('case_number');
            $table->foreignIdFor(LawCategory::class);
            $table->foreignIdFor(Law::class)->nullable();
            $table->foreignIdFor(Cases::class, 'original_case_id')->nullable()->constrained('cases','id')->onDelete('set null');
            $table->timestamps();
        });

log

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 INFO  Running migrations.  

2025_02_26_063944_create_case_records_table ........................ 1s FAIL
{"message":"SQLSTATE[42830]: Invalid foreign key: 7 ERROR:  there is no unique constraint matching given keys for referenced table \"cases\" (Connection: pgsql, SQL: alter table \"cases\" add constraint \"cases_original_case_id_foreign\" foreign key (\"original_case_id\") references \"cases\" (\"id\") on delete set null)","context":{"exception":{"class":"Illuminate\\Database\\QueryException","message":"SQLSTATE[42830]: Invalid foreign key: 7 ERROR:  there is no unique constraint matching given keys for referenced table \"cases\" (Connection: pgsql, SQL: alter table \"cases\" add constraint \"cases_original_case_id_foreign\" foreign key (\"original_case_id\") references \"cases\" (\"id\") on delete set null)","code":42830,"file":"/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Connection.php:823","trace":["/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Connection.php:777","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Connection.php:558","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Schema/Blueprint.php:120","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Schema/Builder.php:619","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Schema/Builder.php:473","/var/www/html/vendor/laravel/framework/src/Illuminate/Support/Facades/Facade.php:361","/var/www/html/database/migrations/2025_02_26_063944_create_case_records_table.php:19","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Migrations/Migrator.php:507","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Migrations/Migrator.php:432","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Concerns/ManagesTransactions.php:32","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Migrations/Migrator.php:440","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Migrations/Migrator.php:244","/var/www/html/vendor/laravel/framework/src/Illuminate/Console/View/Components/Task.php:40","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Migrations/Migrator.php:798","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Migrations/Migrator.php:244","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Migrations/Migrator.php:211","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Migrations/Migrator.php:138","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Console/Migrations/MigrateCommand.php:117","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Migrations/Migrator.php:658","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Console/Migrations/MigrateCommand.php:110","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Console/Migrations/MigrateCommand.php:89","/var/www/html/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php:36","/var/www/html/vendor/laravel/framework/src/Illuminate/Container/Util.php:43","/var/www/html/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php:96","/var/www/html/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php:35","/var/www/html/vendor/laravel/framework/src/Illuminate/Container/Container.php:754","/var/www/html/vendor/laravel/framework/src/Illuminate/Console/Command.php:213","/var/www/html/vendor/symfony/console/Command/Command.php:279","/var/www/html/vendor/laravel/framework/src/Illuminate/Console/Command.php:182","/var/www/html/vendor/symfony/console/Application.php:1094","/var/www/html/vendor/symfony/console/Application.php:342","/var/www/html/vendor/symfony/console/Application.php:193","/var/www/html/vendor/laravel/framework/src/Illuminate/Foundation/Console/Kernel.php:198","/var/www/html/vendor/laravel/framework/src/Illuminate/Foundation/Application.php:1235","/var/www/html/artisan:16"],"previous":{"class":"PDOException","message":"SQLSTATE[42830]: Invalid foreign key: 7 ERROR:  there is no unique constraint matching given keys for referenced table \"cases\"","code":42830,"file":"/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Connection.php:569","trace":["/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Connection.php:569","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Connection.php:810","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Connection.php:777","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Connection.php:558","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Schema/Blueprint.php:120","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Schema/Builder.php:619","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Schema/Builder.php:473","/var/www/html/vendor/laravel/framework/src/Illuminate/Support/Facades/Facade.php:361","/var/www/html/database/migrations/2025_02_26_063944_create_case_records_table.php:19","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Migrations/Migrator.php:507","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Migrations/Migrator.php:432","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Concerns/ManagesTransactions.php:32","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Migrations/Migrator.php:440","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Migrations/Migrator.php:244","/var/www/html/vendor/laravel/framework/src/Illuminate/Console/View/Components/Task.php:40","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Migrations/Migrator.php:798","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Migrations/Migrator.php:244","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Migrations/Migrator.php:211","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Migrations/Migrator.php:138","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Console/Migrations/MigrateCommand.php:117","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Migrations/Migrator.php:658","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Console/Migrations/MigrateCommand.php:110","/var/www/html/vendor/laravel/framework/src/Illuminate/Database/Console/Migrations/MigrateCommand.php:89","/var/www/html/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php:36","/var/www/html/vendor/laravel/framework/src/Illuminate/Container/Util.php:43","/var/www/html/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php:96","/var/www/html/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php:35","/var/www/html/vendor/laravel/framework/src/Illuminate/Container/Container.php:754","/var/www/html/vendor/laravel/framework/src/Illuminate/Console/Command.php:213","/var/www/html/vendor/symfony/console/Command/Command.php:279","/var/www/html/vendor/laravel/framework/src/Illuminate/Console/Command.php:182","/var/www/html/vendor/symfony/console/Application.php:1094","/var/www/html/vendor/symfony/console/Application.php:342","/var/www/html/vendor/symfony/console/Application.php:193","/var/www/html/vendor/laravel/framework/src/Illuminate/Foundation/Console/Kernel.php:198","/var/www/html/vendor/laravel/framework/src/Illuminate/Foundation/Application.php:1235","/var/www/html/artisan:16"]}}},"level":400,"level_name":"ERROR","channel":"local","datetime":"2025-03-21T18:10:28.023448+00:00","extra":{}}

In Connection.php line 823:
                                                                             
SQLSTATE[42830]: Invalid foreign key: 7 ERROR:  there is no unique constrai  
nt matching given keys for referenced table "cases" (Connection: pgsql, SQL  
: alter table "cases" add constraint "cases_original_case_id_foreign" forei  
gn key ("original_case_id") references "cases" ("id") on delete set null)    
                                                                             

In Connection.php line 569:
                                                                             
SQLSTATE[42830]: Invalid foreign key: 7 ERROR:  there is no unique constrai  
nt matching given keys for referenced table "cases"                          
                                                                             

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