rluvaton

export enum MongoErrorCode {
    OK = 0,
    InternalError = 1,
    BadValue = 2,
    OBSOLETE_DuplicateKey = 3,
    NoSuchKey = 4,
    GraphContainsCycle = 5,
    HostUnreachable = 6,// Categories: NetworkError, RetriableError
    HostNotFound = 7,// Categories: NetworkError, RetriableError
    UnknownError = 8,

eranation

//equivalent of "select count (distinct fieldName) from someTable"
db.someCollection.aggregate([{ $group: { _id: "$fieldName"}  },{ $group: { _id: 1, count: { $sum: 1 } } } ])