blocks|key|4610491|text|在User类中|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4610492|public+function+role()
{
++++//+not+$this->belongsToMany('App\Admin\Role');
++++return+$this->belongsTo('App\Admin\Role');
}|code-block|syntax|javascript|4610493|因为你想要的是oneToMany而不是manyToMany关系。|4610494|entityMap^0|1|4|0|0|7|9|J|A|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|N|$]]

In the <code>User</code> class

<pre><code>public function role()
{
 // not $this-&gt;belongsToMany('App\Admin\Role');
 return $this-&gt;belongsTo('App\Admin\Role');
}
</code></pre>

Because you want a <code>oneToMany</code> not <code>manyToMany</code> relationship.

blocks|key|1191306|text|这样就行了。请试试看|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1191307|class+User+extends+Model+
{
++++public+function+role()
++++{
++++++++return+$this->hasOne(App\Admin\Role::class);
++++}
}

//+user+belongs+to+one+role
class+Role+extends+Model
{

++++protected+$table+=+'roles';

++++public+function+users()
++++{
++++++++return+$this->belongsTo(App\Admin\User::class);
++++}

}|code-block|syntax|javascript|1191308|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This should do it. Please give it a try

<pre><code>class User extends Model 
{
 public function role()
 {
 return $this-&gt;hasOne(App\Admin\Role::class);
 }
}

// user belongs to one role
class Role extends Model
{

 protected $table = 'roles';

 public function users()
 {
 return $this-&gt;belongsTo(App\Admin\User::class);
 }

}
</code></pre>

blocks|key|4610534|text|用户模型|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4610535|class+User+extends+Authenticatable{

++public+function+roles(){
++++return+$this->belongsTo('App\Admin\Role');
++}
+++}|code-block|syntax|javascript|4610536|角色模型|4610537|++++class+Role+extends+Model{

+++++public+function+users(){
+++++++return+$this->hasMany('App\Admin\User');
+++++}
++++++}|4610538|用户只能有一个角色，该角色可以分配给许多用户。|4610539|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

User Model

<pre><code>class User extends Authenticatable{

 public function roles(){
 return $this-&gt;belongsTo('App\Admin\Role');
 }
 }
</code></pre>

Role Model

<pre><code> class Role extends Model{

 public function users(){
 return $this-&gt;hasMany('App\Admin\User');
 }
 }
</code></pre>

The user can have only one role, and the role can be assigned to many users.

blocks|key|4696824|text|只要确定一下关系|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4696825|A用户hasOne角色|unordered-list-item|offset|length|style|BOLD|4696826|A角色belongsToMany用户|4696827|所以，在这种情况下|4696828|class+User+extends+Model+
{
++++public+function+role()
++++{
++++++++return+$this->hasOne('App\Admin\Role');
++++}
}
class+Role+extends+Model
{

++++protected+$table+=+'roles';

++++public+function+users()
++++{
++++++++return+$this->belongsToMany('App\Admin\User');
++++}
}|code-block|syntax|javascript|4696829|并且必须在角色迁移表中检查user_id外部约束是否“无符号”。|4696830|entityMap^0|0|0|B|0|0|I|0|0|0|0^^$0|@$1|2|3|4|5|6|7|V|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|W|8|@$E|X|F|Y|G|H]]|9|@]|A|$]]|$1|I|3|J|5|D|7|Z|8|@$E|10|F|11|G|H]]|9|@]|A|$]]|$1|K|3|L|5|6|7|12|8|@]|9|@]|A|$]]|$1|M|3|N|5|O|7|13|8|@]|9|@]|A|$P|Q]]|$1|R|3|S|5|6|7|14|8|@]|9|@]|A|$]]|$1|T|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|U|$]]

Just make sure the relation

<ul>
<li>A User hasOne Role</li>
<li>A Role belongsToMany Users</li>
</ul>

so, in this condition

<pre><code>class User extends Model 
{
 public function role()
 {
 return $this-&gt;hasOne('App\Admin\Role');
 }
}
class Role extends Model
{

 protected $table = 'roles';

 public function users()
 {
 return $this-&gt;belongsToMany('App\Admin\User');
 }
}
</code></pre>

and must check your user_id foreign constraint be 'unsigned' in your role migration table.

I am trying to create one-to-many relationship with 2 models, <code>User</code> and <code>Role</code>. So, I would like that one <code>User</code> can only have one role, and the <code>Role</code> can be assigned to more than <code>User</code>. I tried to follow the offical tutorial on <a href="https://laravel.com/docs/5.1/eloquent-relationships#one-to-many" rel="nofollow">https://laravel.com/docs/5.1/eloquent-relationships#one-to-many</a>, and ended up with this:

<pre><code>class User extends Model 
{
 public function role()
 {
 return $this-&gt;belongsToMany('App\Admin\Role');
 }
}

class Role extends Model
{

 protected $table = 'roles';

 public function users()
 {
 return $this-&gt;hasMany('App\Admin\User');
 }

}
</code></pre>

Based on that link, I think the <code>Role</code> is the same thing as the <code>Post</code>, one <code>Role</code> can be assigned to many <code>User</code>. However, this doesn't quite work, here is how I tried to access the role name for a specific <code>User</code>

<pre><code>$role_first = $user-&gt;role; // Eloquent\Collection
$role_second = $user-&gt;role(); // Eloquent\Relations\BelongsToMany

$role_first-&gt;role_title // 'Undefined property: Illuminate\Database\Eloquent\Collection::$role_title'
$role_second-&gt;role_title // exception 'ErrorException' with message 'Undefined property: Illuminate\Database\Eloquent\Relations\BelongsToMany::$role_title'
</code></pre>

What is exactly wrong here?

one-to-many relationship doesn't work

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我正试图建立一对多的关系与2种模式，User和Role。因此，我希望一个User只能有一个角色，并且Role可以分配给多个User。我试着学习关于的官方教程，最后得到了以下内容：class User extends Model {    public function role()    {        return...

问一对多的关系行不通
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