How to add a foreign key to a table after migration done laravel

it will make ur tables and fill them with data as they was

Advice: don't play with database in production

1.Go to your database
2.Click your table column
3.Click structure on menu bar
4.Click Relation view 

U can add foreign key whatever u want.

Btw, don't forget to edit your current migration table and add foreign field in your project.

i tried ur method by following through net, but i face problem. violation error, add or update foreign key

like this it showed error.

the idea is tooo big. i just made sql commands i did it.

ALTER TABLE `users`
    ADD COLUMN `hotel_id` INT(10) unsigned AFTER `user_name`;


ALTER TABLE `users`
  ADD KEY `users_hotel_id_foreign` (`hotel_id`);



ALTER TABLE `users`
  ADD CONSTRAINT `users_hotel_id_foreign` FOREIGN KEY (`hotel_id`) REFERENCES `hotel_registrations` (`id`);

it succesfully done.. but really thank you soo much for ur suggestion and help.

really it helped me lot

i tried

php artisan make:migration add-hotel-to-tables --table=products

and changed to

 $table->integer('hotel_id')->unsigned()->after('id')->nullable();
            $table->foreign('hotel_id')->references('id')->on('hotel_registrations');

php artisan migrate worked correctly

but in the same migration file if i just change the table name and do php artisan migrate then it says nothing to migrate.

so i followed sql commands

//this is for users table

ALTER TABLE `users`
    ADD COLUMN `hotel_id` INT(10) unsigned AFTER `user_name`;


ALTER TABLE `users`
  ADD KEY `users_hotel_id_foreign` (`hotel_id`);



ALTER TABLE `users`
  ADD CONSTRAINT `users_hotel_id_foreign` FOREIGN KEY (`hotel_id`) REFERENCES `hotel_registrations` (`id`);

just i made duplication of this code and changed the table name and foreign key name thats it.

for all tables the column with primary key is added.

but really u gave much more explanation thank you thank youuu soooo much..

and for If you have 26 tables though, with data you cannot lose, I have not a clue how you will populate these tables with the hotel_id value?

for this answer is

i will do

where ('hotel_id',Auth::user()->hotel_id)

so based on this the records are fetched.

Kindly refer this link: https://laracasts.com/discuss/channels/laravel/guys-need-a-big-suggestion-for-login-permission-for-different-users-laravel

for my changes plz

but using sql cmd u will lose your settings by losing the data or changing the environment

php artisan make:migration add_foreign_key --table=products

Add Column

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

    // To Create column
    $table->unsignedInteger('product_category_id')->nullable()->references('id')->on('categories');
});

Updating Column

Schema::table('products', function (Blueprint $table) {
   
    // Change to UnsignedInteger
    $table->unsignedInteger('product_category_id')->change();
    
    // Updating relationships
    $table->foreign('product_category_id')->references('id')->on('categories')->change();
});

This changes will not remove any data from your DB. But anyways TEST IT before do anything on your production DB. Let me know if you have any questions.

but runnig rollback will erase data coz it will drop last migrations

i hope it work for him

you can repeat this in the same file for all your other tables

In the same file - not by changing the code you already ran;

Schema::table('product', function (Blueprint $table) {
    $table->unsignedInteger('hotel_id')->nullable();
});

Schema::table('purchase', function (Blueprint $table) {
    $table->unsignedInteger('hotel_id')->nullable();
});

Schema::table('bookings', function (Blueprint $table) {
    $table->unsignedInteger('hotel_id')->nullable();
});

Schema::table('staff', function (Blueprint $table) {
    $table->unsignedInteger('hotel_id')->nullable();
});

... whatever, whatever

Start hacking away with phpmysql and you will soon forget all the changes you made and will be unable to reliably perform the same on production.

You also then have database state that is not in your code repo and cannot be rebuilt by someone else.

as i said i tried the sql commands it was some what easy.

but thank you so much for your response

ya i understood that changing in the single file and if i migrate it it works.

Start hacking away with phpmysql and you will soon forget all the changes you made and will be unable to reliably perform the same on production.

this you are saying that changing in sql cannot be remembered for future so there i will face problems thats what u are trying to say??

You also then have database state that is not in your code repo and cannot be rebuilt by someone else. whats this meaning???

i agree with you.

as you said i need to learn about migrations.

thank you for you suggestions..

namespace App\Http\Controllers;

use Illuminate\Http\Request; use Illuminate\Support\Facades\DB; use Illuminate\Support\Facades\Validator; use Illuminate\Support\Facades\Schema; use App\Image; use Illuminate\Database\Migrations\Migration; use Illuminate\Database\Schema\Blueprint;

class Foreignkey extends Migration { function index(){

    Schema::table('images', function (Blueprint $table) {
       

        $table->foreign('sub_cat_id')
            ->references('id')
            ->on('subcategories')
            ->onDelete('cascade');
    });
}

} 4- Go to data base and delete old primary key manualy from the table