Laravel one-to-many relationship - a reference to a non-existent field - php

Question

What do I forget about doing migrations in Lavarel that once relations act to me like this and once so? Presenting what I want to get is I want to assign the user his order and order the products he ordered. So I have a User table, the Order table, and the OrderProduct table. Usera table with one-to-many relation with the Order table, Order table with one-to-many relation with the OrderProduct table. Starting from the relation Order and OrderProduct, I get an error:
SQLSTATE[42S22]: Column not found: 1054 Unknown column 'order_products_tables.order_table_id' in 'where clause' (SQL: select * from `order_products_tables` where `order_products_tables`.`order_table_id` = 1 and `order_products_tables`.`order_table_id` is not null)
And this error says clearly and clearly that he can not find the order_table_id column in the order_products_tables table and I am not surprised what it may sound silly because there is no such field but there is an order_id field and in migrations is described with which field is the relationship and I can not understand why Laravel tries refer to order_products_tables.
Migrations Order:
Schema::create('order_tables', function (Blueprint $table) {
$table->increments('id');
$table->integer('user_id')->unsigned()->nullable();
$table->foreign('user_id')
->references('id')
->on('users');
$table->timestamps();
});
Migrations OrderProduct:
Schema::create('order_products_tables', function (Blueprint $table) {
$table->increments('id');
$table->integer('order_id')->unsigned();
$table->integer('count')->unsigned();
$table->integer('price')->unsigned();
$table->foreign('order_id')
->references('id')
->on('order_tables');
$table->timestamps();
});
As it results from the migration, the order_products_tables table stores the record ID from the order_tables table and the relationship is based on that ID.
Model Order table:
class OrderTable extends Model
{
protected $table = 'order_tables';
public function user()
{
return $this->belongsTo(User::class, 'id');
}
public function products()
{
return $this->hasMany('App\OrderProductTable');
}
}
Model OrderProduct table:
class OrderProductTable extends Model
{
protected $table = 'order_products_tables';
public function order()
{
return $this->belongsTo(OrderTable::class, 'id');
}
}
I do not understand why the reference to order_table_id is going. I have done other relations, eg User and Order on the same principle, and it works without a problem, suddenly here I have such a case. Where should I look for a solution and why does it wo

Answer 1

This error comes from using wrong table names or, to be more correct, not defining the relationship correctly. The following relationship definitions will fix your issue:
class OrderTable extends Model
{
protected $table = 'order_tables';
public function products()
{
return $this->hasMany('App\OrderProductTable', 'order_id', 'id');
}
}
class OrderProductTable extends Model
{
protected $table = 'order_products_tables';
public function order()
{
return $this->belongsTo(OrderTable::class, 'order_id', 'id');
}
}
The reason your previous code did not work is that Laravel uses default values which are basically assumptions and require your database to follow certain naming conventions. Here is a list of conventions you should follow*:
Tables should be named after the model name in plural form and snake_case:
Model User is supposed to have a table named users.
Model Category is supposed to have a table named categories (see the english plural).
Model AccountManager is supposed to have a table named account_managers.
If there is no model for a table, i.e. a many-to-many relationship table, the table name is expected to be in singular form and snake_case, where the model names that hold the relation are ordered alphabetically:
If there are models Category and Product (with tables categories and products) and there is a many-to-many relationship (belongsToMany()) between them, the table for the pivot table is expected to be called order_product (and not product_order because o comes before p in the alphabet).
Foreign key columns are expected to be called after the model they represent with _id as postfix:
When referencing the User model on a BlogPost model for example, Laravel expects a user_id column as foreign key on the BlogPost model. The referenced primary key on the User model is taken from the $primaryKey property, which is 'id' by default.
For your particular scenario, this means we would expect the following models, tables and columns:
Model User with table users and columns like in the default migration of Laravel.
Model Order with table orders and columns like id, user_id, created_at, ...
Model Product with table products and columns like id, name, price, ...
Model OrderProduct with table order_products and columns like id, order_id, product_id, quantity, ...
In theory, the model OrderProduct is not necessary. You should also be able to build the same system without it by defining $this->belongsToMany(Product::class)->withPivot('quantity') on the Order model and $this->belongsToMany(Order::class)->withPivot('quantity') on the Product model (note the pivot fields). Personally, I prefer extra models for many-to-many relations though.
For reference to Eloquent relationships, have a look at the documentation. There are examples for all relationship types and additional information for the additional parameters when you need to override the default table or column names for your relations.
* This list may lack important information. It was created as best effort.