使用_t定义查询C＃驱动程序插入的记录

Question

I want to query data which was inserted by C# mongodriver with polymorhism. The query will be done by Golang driver. Structure of the data is shown below. I want to map _t to structs, in other words, I want to apply polymorhism to record in Go. Is it possible to do it in Golang mongo drivers? The list of structs is below as well.

One record example from mongo collection

{"_id" : "asdasda12312312asdasda",
"structure" : [ 
                    {
                        "_t" : "AObject",
                        "Text" : "asdasdasda",
                        "State" : "asdasda"
                    }, 
                    {
                        "_t" : "BObject",
                        "Number" : "123",
                    }, 
                    {
                        "_t" : "CObject",
                        "Testing" : "Pompeo"
                    }
                ]
}

Go Structs

type Data struct{
  _id string
  Structure []Object
}

type Object interface{
}

type AObject struct {
  Text  string
  State string 
}
type BObject struct {
  Number  string 
}
type CObject struct {
  Testing  string
}

Thanks

Answer 1

What mongo driver are you using? "_t" is a parameter used to determine what type was serialized if the current type is different than the nominal type. It's also used for normal JSON serialization so you have one of three ways I can think of.

1. Using different GO mongo driver which supports it. I would suggest using https://github.com/mongodb/mongo-go-driver which is official MongoDB Go Driver
2. Write switch / case statement to deserialize it yourself

type MongoObject struct {
        // Contains all fields from all objects
        _t string
        Text string
        State string
        Number string
        Testing string
}

func DeserializeObject(object MongoObject) Object{
        switch t {
        case "AObject":
        return &AObject{Text: object.Text, State: object.State}
        case "BObject":
        return &BObject{Number: object.Text}
        case "CObject":
        return &CObject{Testing: object.Testing}
    }
}

1. You can get data from mongo as JSON and use certain marshaling to do it for you