before everything, I tried hard many websites and forums to solve this problem until these posts related to this problem in StackOverflow, but I can't solve the problem. I want to create to one to many relationship between Post and Category model but I get that error code.
SQLSTATE[HY000]: General error: 1005 Can't create table school
. posts
(errno: 150 "Foreign key constraint is incorrectly formed") (SQL: alter table posts
add constraint posts_category_id_foreign
foreign key ( category_id
) references categories
( id
) on delete cascade)
Schema::create('categories', function (Blueprint $table) {
$table->id();
$table->string('name');
$table->string('slug');
$table->timestamps();
});
Schema::create('posts', function (Blueprint $table) {
$table->id();
$table->integer('category_id')->unsigned();
$table->foreign('category_id')->nullable()->references('id')->on('categories');
$table->string('title')->nullable();
$table->timestamps();
});
}
class Category extends Model
{
use HasFactory;
protected $table = 'categories';
protected $guarded = [];
public function posts(){
return $this->hasMany(Post::class);
}
}
class Post extends Model
{
use HasFactory;
protected $guarded = [];
public function category(){
return $this->belongsTo(Category::class);
}
}
please help me I appreciate your help.
Your foreign_key
field and your id
should be of the same type, for example, if categories.id
is bigIncrements
, your foreign_key
inside your Post table
also should be bigInteger
.
Category Table
Schema::create('categories', function (Blueprint $table) {
$table->bigIncrements('id');
$table->string('name');
$table->string('slug');
$table->timestamps();
});
Post Table
Schema::create('posts', function (Blueprint $table) {
$table->id();
$table->bigInteger('category_id')->unsigned()->nullable();
$table->foreign('category_id')->references('id')->on('categories')->onDelete('cascade');
$table->string('title')->nullable();
$table->timestamps();
});
Note : You should make sure, your Category Table migration is running before Post Table migration.
$table->id();
creates an unSignedBigInteger
(UNSIGNED BIGINT) .
$table->integer('category_id')->unsigned();
creates an unSignedInteger
. (UNSIGNED INTEGER) .
// Instead of:
$table->integer('category_id')->unsigned(); ❌
// Use this:
$table->unsignedBigInteger("category_id")->nullable(); ✅
$table->foreign("category_id")
->references("id")
->on("categories")
->onDelete("set null");
Delete Foreign Key Contsraints From bottom of your table
Please see a screenshot here
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