laravel通过数据库检查和插入，没有重复

Question

我已经解决了我的一个问题

1. 首先是用户无法添加自己的数据（已解决）
2. 将他的部门成员添加到同一文件/文档上一次。
3. 不应该使用相同的用户再次添加

当我再次向用户分享文件时，它再次添​​加我确定有一种方法可以验证。事情是我在这个框架上是新手。我在谷歌上找到的东西并没有帮助我。

     //getting the initial request 
        $cruds_initials = DB::table('cruds')->where('id',$id)->first();

        $cruds_initials->document;
        $cruds_initials->year_release;
        $cruds_initials->item_code;
        $cruds_initials->file;
        $cruds_initials->user_id;
        $cruds_initials->sharetoken;
        $cruds_initials->privacy;
        $cruds_initials->document_owner;
        $cruds_initials->created_at;
        $cruds_initials->updated_at;

        //checking the tables if the initial request has values
        $cruds = DB::table('cruds')->where('id', $id)->get();
        $user_name = $request->Division;
        $users = DB::table('users')->where('division' ,$user_name)->get();

        //looping through database that has users + cruds database
foreach($users as $key){
    foreach($cruds as $cey){


        $user_id = $key->id;
        $cruds_id = $key->id;
        $cruds_owner = $cey->document_owner;
        $cruds_division = $cey->division;
        $cruds_document = $cey->document;
        $cruds_year_release = $cey->year_release;
        $cruds_sharetoken = $cey->sharetoken;
        $cruds_privacy = $cey->privacy;
        $cruds_item_code = $cey->item_code;
        $cruds_file = $cey->file;
        $cruds_created_at = $cey->created_at;
        $cruds_updated_at = $cey->updated_at;

    // 1 do not add the users that will share the file
       if(Auth::id() == $user_id){
            echo "don't insert my id <br>";
            continue;

       }else{  
   // 2 to add the users who dont have the files 
   // 3 do not add the users who already have the files
                if($user_id <>  $cruds_owner ){
                    $result=DB::table('cruds')->insert([

                    'division'         => $cruds_division, 
                    'document'         => $cruds_document,
                    'year_release'     => $cruds_year_release,
                    'item_code'        => $cruds_item_code,
                    'file'             => $cruds_file,
                    'user_id'          => $user_id,     //share to this user
                    'sharetoken'       => $cruds_sharetoken,
                    'privacy'          => $cruds_privacy,
                    'document_owner'   => $cruds_owner,   //user who owns the file
                    'created_at'       => $cruds_created_at,
                    'updated_at'       => $cruds_updated_at

                    ]);
                    continue;

                }else{
                    echo "<hr>not insert";
                } 
            }
            continue;
    }
}