Laravel:基于条件创建HasMany关系

本文介绍了Laravel:基于条件创建HasMany关系的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我需要根据性别状况显示复制品

I need to display reproductions based on Gender Condition

复制表:

$table->bigIncrements('id'); $table->unsignedInteger('father_id'); $table->unsignedInteger('mother_id'); ...

我需要根据性别检索复制品

I need to retrieve reproductions according to the gender

User.php

public function reproductions(){ if($this->gender == 'm'){ return $this->hasMany(Reproduction::class, 'father_id'); }else{ return $this->hasMany(Reproduction::class, 'mother_id'); } }

复制表:

id father_id mother_id 1 1 2 2 1 3 3 1 4

当我为ID为1的用户检索复制时，它需要显示3个复制，但返回空集合

When I retrieve reproduction for User with id 1, it needed to display 3 reproductions but it returns null collection

$firstUser = User::find(1); // User Id with 1 has gender m dd($firstUser->reproductions->count()); // Should return 3 but returns null collection

推荐答案

，您可以创建两个不同的关系.

you can create two different relationships.

public function maleReproductions(){ return $this->hasMany(Reproduction::class, 'father_id'); }

public function feMaleReproductions(){ return $this->hasMany(Reproduction::class, 'mother_id'); }

现在基于 $ user ，您可以附加关系.

now based on $user you can attach relationship.

$productions = []; $user = User::where('id',1)->first(); if($user->gender == 'm'){ $productions = $user->maleProductions; } else { $productions = $user->feMaleProductions; }

要收集用户，请同时附加两个关系.并根据条件进行特定的访问.

for collection of users, attach both relationship. and access specific based on condition.

$users = User::with('maleReproductions', 'femaleReproductions')->get(); foreach($users as $user){ if($user->gender == 'm'){ $productions = $user->maleProductions; } else { $productions = $user->feMaleProductions; } }