CakePHP 3.x 数据库映射，BelongsToMany 与 HasMany+HasOne

Question

我在数据库中有三个表：(1) offers, (2) offer_rows, (3) 产品.

offer_rows 将始终指向 offer，并且可能（但不总是）指向产品。 offer_rows还有价格等其他字段

与（我的）相同SQL:

create table offers(
    id serial not null auto_increment primary key,
    ...
);
create table offer_rows(
    id serial not null auto_increment primary key,

    product_id bigint(20) unsigned references products(id),
    offer_id bigint(20) unsigned not null references offers(id),

    price decimal(15,2),
    ...
);
create table products(
    id serial not null auto_increment primary key,
    ...
);

就 CakePHP (3.3.16) 而言，对产品的可选引用，正确的映射是什么？

如果 offer_rows 对产品引用有非空限制（目前没有），那么 BelongsToMany 应使用：

(class OffersTable)
@property \Cake\ORM\Association\BelongsToMany $Products

// initialize
$this->belongsToMany('Products', [
     'through' => 'OfferRows',
     'foreignKey' => 'offer_id',
     'joinType' => 'INNER',
     'joinTable' => 'offer_rows',
]);


(class OfferRowsTable)
@property \Cake\ORM\Association\BelongsTo $Products
@property \Cake\ORM\Association\BelongsTo $Offers

// initialize
$this->belongsTo('Products', [
     'foreignKey' => 'product_id'
]);
$this->belongsTo('Offers', [
     'foreignKey' => 'offer_id',
     'joinType' => 'INNER'
]);


(class ProductsTable)
@property \Cake\ORM\Association\BelongsToMany $Offers

// initialize
$this->belongsToMany('Offers', [
     'through' => 'OfferRows',
     'foreignKey' => 'product_id',
     'joinType' => 'INNER',
     'joinTable' => 'offer_rows',
]);

但是，有可能出现空积，我应该改用 HasMany + HasOne 吗？

(class OffersTable)
@property \Cake\ORM\Association\HasMany $OfferRows

// initialize
$this->hasMany('OfferRows', [
    'foreignKey' => 'offer_id'
]);

(class OfferRowsTable)
@property \Cake\ORM\Association\BelongsTo $Offers
@property \Cake\ORM\Association\HasOne $Products

// initialize
$this->belongsTo('Offers', [
       'foreignKey' => 'offer_id',
       'joinType' => 'INNER'
]);        
$this->hasOne('Products', [
    'className' => 'Products',
        'propertyName' => 'reference_product_obj',
        'foreignKey' => 'reference_product'             
]);

(class ProductsTable)
@property \Cake\ORM\Association\BelongsToMany $OfferRows

// initialize
$this->belongsToMany('OfferRows', [
    'foreignKey' => 'product_id',
    'joinType' => 'INNER',
]);

有一个是正确的，还是有第三个选择？

Answer 1

如果您需要检索连接 table 数据，而不管产品是否存在/是否已链接，那么您应该采用类似于后一种解决方案的方法。

但是 OfferRowsTable class 中的 Products 关联应该是 belongsTo 关联，因为 hasOne 期望目标中存在外键table，即productstable。使用 hasOne 最晚会在保存关联时破坏内容。

此外 ProductsTable class 中的 belongsToMany 关联应该指向 Offers，而不是 OfferRows。

CakePHP 3.x 数据库映射，BelongsToMany 与 HasMany+HasOne

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