对象Golang中的对象中的对象

I'm attempting to create nested objects in mongoDB with no luck the format I am trying to achieve is as follows

 "Courses":{
    "Date":{
      "CourseName"  :{
                "hole 1"{

                }
                "hole 2"{

                }
                ...so on until 18 
               }//coursename
             }//date 
          }//courses

I've tried and succeeded with getting the date object within course by doing the following:

u := req.FormValue("username")
co := req.FormValue("course")
d := req.FormValue("date")

ng := nGame{Username: u, Course: co, Dates: d}
cn := courseName{CName: co}
query := bson.M{"username": u}
update := bson.M{"$push": bson.M{"Course": bson.M{ng.Dates: cn}}}  
err = c.Update(query, update)

The date object has the course name inside it what i'm trying to do is make course name another object which then I can insert the hole object.

The Structs i'm using are as follows:

type (
nGame struct {
    Username string
    Course   string
    Location string
    Dates    string
}
)
type (
courseName struct {
    CName string
}
)

Your described structure, as I understand it, can be represented in Go as follows:

type Hole struct {
    // Whatever you want here
}

type Course struct {
    Hole1 Hole `json:"hole 1"`
    Hole2 Hole `json:"hole 2"`
    // ...
    Hole18 Hole `json:"hole 18"`
}

type Courses struct {
    //  Date       CourseName
    map[string]map[string]Course
}

I would suggest, however, using an 18-element array for your holes, but that's up to you:

type Course struct {
    Holes [18]Hole
}

Then you can instantiate one of these trees as (using a [18]Hole array; adjust accordingly if you use a different implementation):

courses := Courses{
    map[string]map[string]Course{
        "2017-01-01": map[string]Course{
            "Bob's Course": Course{
                [18]Hole{
                    Hole{
                      // Hole 1
                    },
                    Hole{
                      // Hole 2
                    },
                    // ..
                },
            },
        },
    },
}