MongoDB聚合Shell脚本到MongoC#Driver

如何将这个Mongo Shell脚本转换为MongoDB C#驱动程序？

var myItems = []

var myCursor = db.Tickets.aggregate(
   [
      { $match : { TicketProjectID : 49 } },
      { $project: { TicketProjectID:1, TicketID:1, concatValue: { $concat: [ "$Status", " - ", "$Name" ] } } }
    // I will have a list of fields that I need to concatenate at run time. So C# query should support concatenation for "N" number of fields at run-time.
      //{ $group: { _id: null, count: { $sum: 1 } } }

   ],
      { allowDiskUse: true }
)

   //This seems like a ugly performance approach when we are working against 100k results with above match
     while (myCursor.hasNext()) {
         var item = myCursor.next();
         if(item.concatValue.search(/mysearchkey/i) > -1)
             {
                myItems.push(item.TicketID)
             }
    }    
    myItems

或者有更好的方法在连接投影中进行字符串搜索而不是游标中的foreach,因为一些quires可能获得50k记录.

这是我到目前为止所尝试的,(不使用聚合)

注意：修改此代码以适应公共Q& A站点.所以请将此视为伪代码

 var tickets = ticketsCollection.FindSync(filter).ToList();
                string concatinatedValue = string.Empty;
                foreach (var ticket in tickets)
                {
                    foreach (var field in customFieldsForThisProject)
                        concatinatedValue += ticket[field.Replace(" ", "_")];

                  if(concatinatedValue.StripHtml().contains("MysearchWord"))
                 {
                   TikectIdList.Add(ticket["TicketID"])
                 }
                }

解决方法:

根据给定的评论编辑

如果你可以使用AsQueryable(),你可以得到这样的值：

var dbResult = from ticket in ticketsCollection.AsQueryable()
               where ticket.TicketProjectID == 49
               select new 
               {
                   TicketProjectID = ticket.TicketProjectID,
                   TicketID = ticket.TicketID,
                   ConcatValue = ticket.Status + " - " + ticket.Name
               };

而且以后你可以这样做：

var result = from dbr in dbResult
             where dbr.ConcatValue.Contains("something") //or
             where dbr.ConcatValue.StartsWith("something")//or you can use regex
             select dbr;

Note: For some reason both Status and Name properties from type Ticket need to be of a type String for concatenation to work since mongo driver won’t recognize the call to ToString() from some other type.

如果要从其他类型连接属性,可以将它们与db分开,而不是在本地连接它们.

请注意,我对mongo shell不太好,我可以搞砸一些东西,但你可以看到你可以去哪种方式

或者,您可以像这样编写shell命令并将其放在一个字符串中：

var command = @"db.Tickets.aggregate(
[
    { $project: { TicketProjectID:1, TicketID:1, concatValue: { $concat: [ "$Status", " - ", "$Name" ] } } },
    { $match : { TicketProjectId : 49, concatValue : { $regex : /mysearchkey/i } } }
],
{ allowDiskUse : true }
);";

然后使用MongoDatabase中的RunCommandAsync方法在c#中执行它.

var result = await mongoDatabase.RunCommandAsync<BsonDocument>(BsonDocument.Parse(command));

标签：c,shell,mongodb,mongodb-net-driver,mongo-shell
来源： https://codeday.me/bug/20190608/1200090.html