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Data Type Limitations

MongoDB stores data in BSON format. The BSON format has 21 data types. These data types are documented in the MongoDB docs.

The MongoDB C# driver has some limitations when writing C# data models to the database. The driver can't handle all cases of writing unsigned data types like uint to the database. There are two options to handle these unsigned types:

  1. Choose a signed data that can fit the unsigned value (e.g. instead of uint use long)
  2. Annotate the property with BsonRepresentation which defines the type the property is stored as in the database

Example for option two:

public class MyDataModel
{
    [BsonRepresentation(BsonType.Int64)]
    public uint Value { get; set; }
}
danger

Trying to store unsinged values in the database will cause a runtime exception. The exception will look like this:

Unhandled Exception: System.OverflowException: Value was either too large or too small for an Int32.
   at System.Convert.ThrowInt32OverflowException()
   at System.UInt32.System.IConvertible.ToInt32(IFormatProvider provider)
   at MongoDB.Bson.Serialization.Serializers.EnumSerializer`1.Serialize(BsonSerializationContext context, BsonSerializationArgs args, TEnum value)