How to use Auto Increment field in Mongo C# Driver without using eval?

问题

I'm using auto increment fild as discussed here.

I can execute this example in Mongo Console, but how can I implement such a thing using c# driver ?

db.products.insert({
     "_id":getNextSequenceValue("productid"),
     "product_name":"Apple iPhone",
    "category":"mobiles"
})

Is it possible to specify a function in the write operation ?

I could call this function using Eval, but as it is being deprecated, I would like to find a solution without using it.

回答1:

As exemplified here:

var client = new MongoClient(connectionString);
MongoServer server = client.GetServer();
MongoDatabase db = server.GetDatabase("myDatabase");
var counterCol = db.GetCollection("counters")

var result = counterCol.FindAndModify(new FindAndModifyArgs()
{
    Query = Query.EQ(d => d.Id, "orderId"),
    Update = Update.Inc(d => d.Value, 1),
    VersionReturned = FindAndModifyDocumentVersion.Modified,
    Upsert = true, //Create if the document does not exists
});

Using the new v2.x Driver :

public class Sequence
{
    [BsonId]
    public ObjectId _Id { get; set; }

    public string Name { get; set;  }

    public long Value { get; set;  }

    public void Insert(IMongoDatabase database)
    {
        var collection = database.GetCollection<Sequence>("sequence");
        collection.InsertOne(this);
    }

    internal static long GetNextSequenceValue(string sequenceName, IMongoDatabase database)
    {
        var collection = database.GetCollection<Sequence>("sequence");
        var filter = Builders<Sequence>.Filter.Eq(a => a.Name, sequenceName);
        var update = Builders<Sequence>.Update.Inc(a => a.Value, 1);
        var sequence = collection.FindOneAndUpdate(filter, update);

        return sequence.Value;
    }
}

来源：https://stackoverflow.com/questions/50394800/how-to-use-auto-increment-field-in-mongo-c-sharp-driver-without-using-eval

标签

mongodb-.net-driver