mongodb-csharp-2.0

来源： https://stackoverflow.com/questions/30901076/add-element-or-add-to-array-using-mongodb-c-sharp-driver-2-0

来源： https://stackoverflow.com/questions/30901076/add-element-or-add-to-array-using-mongodb-c-sharp-driver-2-0

问题 My goal for this app is to create logic that monitors the database and will trigger actions when a document is added to the database (like sending an email). However, since this application may not be started when a database is first populated, how can I manually create a ResumeToken that points to the very first document that was added into a collection, so that on the first run, I can start at the beginning and iterate through the changes until I reach the end. I recognize that I'll need to

问题 My goal for this app is to create logic that monitors the database and will trigger actions when a document is added to the database (like sending an email). However, since this application may not be started when a database is first populated, how can I manually create a ResumeToken that points to the very first document that was added into a collection, so that on the first run, I can start at the beginning and iterate through the changes until I reach the end. I recognize that I'll need to

问题 I want to perform bulk operation via MongoDb. How to get array of Ids that will be returned after it? Can i perform single-operation insert faster without using bulk ? Can you advise me some other approach ? I'm using C# mongoDb driver 2.0 and MongoDb v. 3.0.2 update: I found the following solution - save maximum ObjectId of mongo collection, db.col.find().sort({_id:-1}).limit(1).pretty() and do the same after insert So we will get the range of inserted documents, does it make a sense? 回答1:

问题 I want to perform bulk operation via MongoDb. How to get array of Ids that will be returned after it? Can i perform single-operation insert faster without using bulk ? Can you advise me some other approach ? I'm using C# mongoDb driver 2.0 and MongoDb v. 3.0.2 update: I found the following solution - save maximum ObjectId of mongo collection, db.col.find().sort({_id:-1}).limit(1).pretty() and do the same after insert So we will get the range of inserted documents, does it make a sense? 回答1:

问题 The new C# driver is totally Async and in my understanding twists a little bit the old design patterns such as DAL in n-tier architecture. In my Mongo DALs I use to do: public T Insert(T entity){ _collection.Insert(entity); return entity; } This way I can get the persisted ObjectId . Today, everything is Async such as InsertOneAsync . How would Insert method will now return the entity when the InsertOneAsync will be done? Can you show an example? 回答1: It's helpful to understand the basics of

问题 A general count query will be doing a int count = collection.Find(filter).Count(); Now that loads all the records as per the filter, so lets says I have 1 million records and out of those 0.5 million match my filter, so I'll have collection already filled with 0.5 documents. This is good enough if you want the documents, but what if you just want to know the count and not really need the documents, for memory sake. Can I do something like this int count = collection.Find(filter).SetLimit(1)

问题 In the old API (1.X) you could tell whether the server was connected or not by using the State property on the MongoServer instance returned from MongoClient.GetServer : public bool IsConnceted { get { return _client.GetServer().State == MongoServerState.Connected; } } However GetServer is not a part of the new API (2.0). How can that be achieved? 回答1: The more appropriate way to do that is not by checking the server but rather the cluster (which may contain multiple servers) and you can

问题 Controller looks like public class NodesRestController : ODataController { private INodeService _nodeService; public NodesRestController(INodeService nodeService) { _nodeService = nodeService; } [EnableQuery()] public IQueryable<Node> Get() { return _nodeService.GetAllNodes(); } [EnableQuery()] public Node Get(string id) { return _nodeService.GetNodeById(id); } } in MongoDb repository i am returning AsQueryable of the collection. //..............Rest of initializations _collection =