Laravel:多对多共享表 [英] Laravel: many-to-many with shared table

问题描述

我有一个Locations模型，其中有很多Employees-类似地Employees属于To Locations

I have Locations model which hasMany Employees -- similarly Employees belongsTo Locations

这很好，效果很好，但是后来我考虑添加PhoneNumbers. Location或Employee都可以具有电话号码(办公室号码与个人号码)

This is nice and works well, but then I looked at adding PhoneNumbers. Either a Location or an Employee could have a phone number (office numbers versus personal numbers)

逻辑上:

Locations hasMany PhoneNumbers(多条办公室线) 和 Employees hasMany PhoneNumbers(家庭/牢房?)

Locations hasMany PhoneNumbers (multiple office lines) and Employees hasMany PhoneNumbers (home / cell ?)

但是，当您在Laravel中创建hasMany关系时，会向PhoneNumbers表中添加一个字段.因此，我们现在有两个字段:location_id和employee_id

However when you create a hasMany relationship like this in Laravel it adds a field to the PhoneNumbers table. So we now have two fields: location_id and employee_id

如果将location_id和employee_id设置为可空，则可以使它正常工作，就像这样:

I can get this to work if I make location_id and employee_id nullable, like so:

+----+--------------+-------------+-------------+
| id |    number    | location_id | employee_id |
+----+--------------+-------------+-------------+
|  1 | 800-555-0123 |      1      |     null    |
|  2 | 800-555-0124 |      1      |     null    |
|  3 | 800-555-0125 |      1      |     null    |
|  4 | 859-555-0199 |     null    |       1     |
                     ...

但是，如果我添加可以拥有电话号码的新实体(客户，求职者或供应商?)，这将无法很好地扩展

However this doesn't scale very well if I add new entities that can possess phone numbers (customers? job applicants? suppliers?)

如何使用同一个辅助表创建多个单独的多对多关系?

注意:在此示例中，我可以在每个单独的表(locations.phone_number，employees.phone_number等)上创建一个phone_number字段，但是出于两个原因，我希望避免这种情况:

Note: In this example I could just create a phone_number field on each individual tables (locations.phone_number, employees.phone_number, etc) however I wish to avoid this for two reasons:

1. 数据完整性(如果所有电话号码都在一个公用表中，则很容易确认未输入重复的电话号码)
2. 绑定到更复杂的模型(用Image替换PhoneNumber，现在您有更多的数据要处理)

1. Data integrity (if all phone numbers are in one common table it's easy to verify duplicate phone numbers are not entered)
2. Binding to more complex models (replace PhoneNumber with Image and now you have a lot more data to deal with)

推荐答案

您正在寻找Laravel的多态关系.您不必为每个相关表创建一个新字段，而要拥有两个字段:相关ID和相关类型.

You're looking for Laravel's polymorphic relationship. Instead of creating a new field for each related table, you have two fields: related id and related type.

在位置"和员工"模型上，添加以下关系:

On both your Location and Employee model, add the following relationship:

public function phones()
{
    return $this->morphMany('PhoneNumber', 'phonable');
}

在您的PhoneNumber型号上，添加以下关系:

On your PhoneNumber model, add the following relationship:

public function phonable()
{
    return $this->morphTo();
}

在phone_numbers表上，添加两个新字段:phonable_type和phonable_id.在迁移中，这些字段是使用morphs()方法添加的:$table->morphs('phonable');

On your phone_numbers table, add two new fields: phonable_type and phonable_id. In a migration, these fields are added with the morphs() method: $table->morphs('phonable');

所有设置完成后，您的数据将如下所示:

Once everything is setup, your data would look like this:

+----+--------------+-------------+---------------+
| id |    number    | phonable_id | phonable_type |
+----+--------------+-------------+---------------+
|  1 | 800-555-0123 |      1      |    Location   |
|  2 | 800-555-0124 |      1      |    Location   |
|  3 | 800-555-0125 |      1      |    Location   |
|  4 | 859-555-0199 |      1      |    Employee   |
                     ...

通过此设置，只需向其添加morphOne()或morphMany()关系即可创建所需的任何模型.

With this setup, you can make any model you want phonable just by adding a morphOne() or morphMany() relationship to it.

此外，关系属性将生成与类型相关的正确模型.鉴于以上数据:

Additionally, the relationship attributes will generate the correct model related to the type. Given the data above:

var_dump(PhoneNumber::find(1)->phonable); // will dump Location object
var_dump(PhoneNumber::find(4)->phonable); // will dump Employee object

可以在此处(4.2)或此处(5.0).

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