如何在 Yii2 的 ON 条件下使用常量 hasMany 关系 [英] How to use constant in the ON condition in Yii2 hasMany relation

问题描述

我尝试创建一个多态关联，这在 Rails 中很常见，但不幸的是在 Yii2 中没有.作为实现的一部分，我需要定义关系:

I try to create a polymorphic association, what is common in Rails but unfortunately not in Yii2. As part of the implementation I need to define the relation:

public function getImages()
{
   return $this->hasMany(RecipeImage::className(), 
       ['imageable_id' => 'id', 'imageable_type' => 'Person']);
}

但这不起作用，因为'Person'被视为当前模型的一个属性，但它是一个常量(多态关联的类名).

But this doesn't work, because 'Person' is treated as an attribute of the current model, but it is a constant (class name for the polymorphic association).

如果我尝试使用andWhere"，它当然会在 WHERE 子句而不是 ON 子句中添加条件，导致仅返回具有现有图像的记录.

If I try to use 'andWhere' it adds the condition of course in a WHERE clause instead of the ON clause, causing that only records with existing image returned.

public function getImages()
{
   return $this->hasMany(RecipeImage::className(), ['imageable_id' => 'id'])->
       andWhere(['imageable_type' => 'Ingredient']);
}

如何定义关系?没有 andOn 方法.

How can I define the relation? There is no andOn method.

推荐答案

在这种情况下，您可以使用 andOnCondition 方法修改 ON 条件:

In this case you can modify ON condition with andOnCondition method:

public function getImages()
{
    return $this->hasMany(RecipeImage::className(), ['imageable_id' => 'id'])
        ->andOnCondition(['imageable_type' => 'Person']);
}

官方文档:

• andOnCondition:

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