f＃使用记录在MongoDB上插入

Question

I've been trying for a while to insert on MongoDB using only records with no success.

My problem is that I want to create a simple insert function which I send a generic type and it is inserted into the database.

Like so.

let insert (value: 'a) = 
    let collection = MongoClient().GetDatabase("db").GetCollection<'a> "col"
    collection.InsertOne value

From this function, I tried inserting the following records.

// Error that it can't set the Id
type t1 = {
    Id: ObjectId
    Text: string
}
// Creates the record perfectly but doesn't generate a new Id
type t2 = {
    Id: string
    Text: string
}
// Creates the record and autogenerates the Id but doesn't insert the Text, and there are two Ids (_id, Id@) 
type t3 = {
    mutable Id: ObjectId
    Text: string
}
// Creates the record and autogenerates the Id but for every property it generates two on MongoDB (_id, Id@, Text, Text@)
type t4 = {
    mutable Id: ObjectId
    mutable Text: string
}

So does anyone can think of a solution for this or am I stuck having to use a class.

// Works!!!
type t5() = 
    member val Id = ObjectId.Empty with get, set
    member val Name = ""  with get, set

Also, does anyone has any Idea of why when the C# MongoDB library translates the mutable he gets the property with the @ at the end? I would be fine with having all my properties set as mutable, although this wouldn't be my first choice, having he create multiple properties on the DB is quite bad.

Answer 1

You could try annotating your records with CLIMutable (and no mutable fields).

The @ s end up in the DB because MongoDB using reflection and F# implementing mutable with backing fields fieldName@