尝试在 laravel 中使用字符串作为外键

Question

我只是一个初学者，尝试在 laravel 中使用字符串作为外键，但在获取数据时出现此错误：-

SQLSTATE[42S22]: Column not found: 1054 Unknown column 'read' in 'where clause' (SQL: select from as sender_id, count(from) as messages_count from messages where to = d3c364bb-0982-46ba-869a-24dbb2c50aea and read = 0 group by from)

在这里我从收到的消息和一组未读消息中获取用户联系人

public function get(){
        $contacts = DB::table('received')
    ->where('user_id', Auth::user()->uuid)
    ->get();
    
     $unreadIds = Message::select(\DB::raw('`from` as sender_id, count(`from`) as messages_count'))
            ->where('to', Auth::user()->uuid)
            ->where('read', false)
            ->groupBy('from')
            ->get();

       
        $contacts = $contacts->map(function($contact) use ($unreadIds) {
            $contactUnread = $unreadIds->where('sender_id', $contact->friends_id)->first();

            $contact->unread = $contactUnread ? $contactUnread->messages_count : 0;

            return $contact;
        });

    return response()->json($contacts);
        }

收到Table:-

 public function up()
    {
        Schema::create('received', function (Blueprint $table) {
            $table->engine = 'InnoDB';
            $table->id();
            $table->string('user_id', 36);
            $table->unsignedBigInteger('friends_id');
            $table->string('list_no')->nullable();
            $table->string('name');
            $table->timestamps();
        });
    }

这是我获取未读消息数的地方：-

public function up()
    {
        Schema::table('messages', function (Blueprint $table) {
            $table->engine = 'InnoDB';
            $table->boolean('read')->after('to', 36)->default(false);
        });
    }

    
    public function down()
    {
        Schema::table('messages', function (Blueprint $table) {
            $table->dropColumn('read');
        });
    }

留言table

public function up()
    {
        Schema::create('messages', function (Blueprint $table) {
           $table->engine = 'InnoDB';
            $table->id();
            $table->string('from', 36);
            $table->string('to', 36);
            $table->text('text');   
            $table->string('list_no')->nullable(); 
            $table->timestamps();
        });
    }

谁能帮我解决这个问题。

Answer 1

仔细查看 sql 错误：形成的查询最初使用“from”而没有任何 table 名称，因为您将“from”用作列名称，即 SQL 查询关键字。

在您的消息 table 迁移中尝试使用不同的列名称可能是“from_user”而不是“来自”并刷新迁移以反映数据库中的更改。

还要在代码中更改相关的列名。

注意 - 除了更改旧迁移，您还可以通过创建新迁移并添加 $table->renameColumn('from', 'from_user');

来更改列名称

尝试在 laravel 中使用字符串作为外键

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