laravel foreign key

1$table->unsignedBigInteger('user_id');
2$table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');

1Schema::table('posts', function (Blueprint $table) {
2    $table->unsignedBigInteger('user_id');
3
4    $table->foreign('user_id')->references('id')->on('users');
5});
6OR
7Schema::table('posts', function (Blueprint $table) {
8    $table->foreignId('user_id')->constrained();
9});

1$table->foreign('column_name')->references('id')->on('table_name')->onDelete('cascade');

1Schema::table('posts', function (Blueprint $table) {
2    $table->unsignedBigInteger('user_id');
3
4    $table->foreign('user_id')->references('id')->on('users');
5});

1use Illuminate\Database\Schema\Blueprint;
2use Illuminate\Support\Facades\Schema;
3
4Schema::table('posts', function (Blueprint $table) {
5    $table->unsignedBigInteger('user_id');
6
7    $table->foreign('user_id')->references('id')->on('users');
8});

1//Note : Before Renaming Foreign, You Must Need To Delete Old Foreign And Assign New One
2class RenameColumn extends Migration
3{
4
5    public function up()
6    {
7        Schema::table('holidays', function(Blueprint $table) {
8            $table->dropForeign('holidays_account_id_foreign');
9            $table->renameColumn('account_id ', 'engagement_id');
10
11            $table->foreign('account_id')->references('id')->on('accounts')->onDelete('cascade');
12        });
13    }
14
15    public function down()
16    {
17        Schema::table('holidays', function(Blueprint $table) {
18            $table->dropForeign('holidays_engagement_id_foreign');
19            $table->renameColumn('account_id ', 'engagement_id');
20
21            $table->foreign('account_id')->references('id')->on('accounts')->onDelete('cascade');
22        });
23    }
24}
25