email as a foreign key in larave-CodePudding

Can I make email as a foreign key ? $table->foreignId('email')->constrained('users')->onDelete('CASCADE'); . I wrote a seeder and is for an integer value for emai. I need to make email unique

This is my users table

        Schema::create('users', function (Blueprint $table) {
        $table->id();
        $table->string('name');
        $table->string('email')->unique();
        $table->timestamp('email_verified_at')->nullable();
        $table->string('password');
        $table->rememberToken();
        $table->timestamps();
    });

CodePudding user response：

To create an Foreign Key association with email column of users table, you cannot use foreignId method as it creates unsignedBigInteger equivalent column.

You can create the foreign key association as

//Some other table - for eg lets say posts
Schema::create('posts', function(Blueprint $table) {
    $table->id();
    $table->string('title');
    $table->text('body');
    $table->string('author_email');

    $table->foreign('author_email') // a column on posts table
        ->references('email') //name of the column on users (referenced) table
        ->on('users')    //name of the referenced table 
        ->onDelete('cascade'); //constrain
});

Then using this foreign key association you can define the author relation in Post model linking it to the User model

//Post.php - eloquent model class
public function author()
{
    return $this->belongsTo(User::class, 'author_email', 'email');
}

Note: For this to work as expected, email column on users table must contain unique values i.e have a unique index (as you have in the migration of users table)

Laravel Docs - Migrations - Foreign Key Constraints