Laravel migration: "Foreign key constraint is incorrectly formed" (errno 150)

@JuanBonnett’s question has inspired me to find the answer. I used Laravel to automate the process without considering the creation time of the file itself. According to the workflow, “meals” will be created before the other table (categories) because I created its schema file (meals) before categories. That was my fault.

When creating a new table in Laravel. A migration will be generated like:

$table->bigIncrements('id');

Instead of (in older Laravel versions):

$table->increments('id');

When using bigIncrements the foreign key expects a bigInteger instead of an integer. So your code will look like this:

public function up()
    {
        Schema::create('meals', function (Blueprint $table) {
            $table->increments('id');
            $table->unsignedBigInteger('user_id'); //changed this line
            $table->unsignedBigInteger('category_id'); //changed this line
            $table->string('title');
            $table->string('body');
            $table->string('meal_av');
            $table->timestamps();

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

            $table->foreign('category_id')
                ->references('id')
                ->on('categories')
                ->onDelete('cascade');
        });
    }  

You could also use increments instead of bigIncrements like Kiko Sejio said.

The difference between Integer and BigInteger is the size:

• int => 32-bit
• bigint => 64-bit