如何避免使用c＃在Mongodb中复制文档

Question

I try to avoid duplicate documents in MongoDB database using asp.net mvc . I used an objectID generated manually but I still get duplicate documents.

this is my code

//collection "Devise1"
public class Devise
{

    public ObjectId id_devise { get; set; }
    public string parité { get; set; }
    public float low { get; set; }
    public float high { get; set; }
   public string date_observation_d { get; set; }
}

---

 //code insertion 
 System.IO.StreamReader file = new System.IO.StreamReader(@"C:\Users\user PC\Desktop\données financiere finale\Classeur1.csv");

    string fileLines;
    try {
        while ((fileLines = file.ReadLine()) != null)
        {
            string[] elements;
            elements = fileLines.Split(new char[] { ' ' });
            for (int x = 0; x < elements.Length; x++)
            {
                devises2.parité = "EUR/USD";
                devises2.id_devise = new ObjectId();

                devises2.date_observation_d = elements[0];

                devises2.low = float.Parse(elements[3], CultureInfo.InvariantCulture.NumberFormat);
                devises2.high = float.Parse(elements[2], CultureInfo.InvariantCulture.NumberFormat);
                collection1.InsertOneAsync(devises2);
            }

        }
    }
    catch(Exception ex)
    {
        throw ex;
    }

Answer 1

Create unique index on id_devise in your collection.

You can create index in your C# application but simple approach will be to run this in your MongoDB shell. See Create Unique Index in MongoDB documentation.