从mongodb中提取嵌套的struct数据

Question

Have a struct as follows

type Person struct {
   ID    bson.ObjectId `bson:"_id,omitempty"`
   Name  string        `json:"name"`
   Phone string        `json:"phone"`
}

and then want to nest it in another struct

type Customer struct {
   ID        bson.ObjectId `bson:"_id,omitempty"`
   StoreName string
   Person    Person        `json:"persons"`
}

instantiated as

customer := Customer{bson.NewObjectId(), "Seattle", p1}

and insterted into Mongo db (I am using the mgo driver for golang)

err = databaseConnection.Insert(&customer)

How do I retrieve the customer struct from the DB using parameters from the nested Person struct? E.g. pull all Customer structs that have a Person struct named “John”

I am trying

err = databaseConnection.Find(bson.M{XXXXXXXXX}).All(&resultsB)

but I can’t figure out what XXXXXX should be.