# Updating graph using struct with uid makes edges disappear (dgo)

**URL:** <https://discuss.dgraph.io/t/updating-graph-using-struct-with-uid-makes-edges-disappear-dgo/7583>\
**Category:** Users\
**Tags:** example, dgo, kind:bug\
**Created:** [July 7, 2020, 9:18am UTC](https://discuss.dgraph.io/t/updating-graph-using-struct-with-uid-makes-edges-disappear-dgo/7583 "2020-07-07T09:18:52Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![AugustDev](https://avatars.discourse-cdn.com/v4/letter/a/9e8a1a/32.png) [@AugustDev](https://discuss.dgraph.io/u/AugustDev)\
**Post date:** [July 7, 2020, 9:18am UTC](https://discuss.dgraph.io/t/updating-graph-using-struct-with-uid-makes-edges-disappear-dgo/7583/1 "2020-07-07T09:18:52Z")

</div>

Hi everyone, I have opened issue to this on dgo github, but I feel it will get more exposure here.

The problem: updating a node causes loss of deeper nested edges using dgo.

Graph before editing `quote`

```json
{
	"uid": "0x2a85",
	"quote": "Moon",
	"car": "Lambo",
	"user.contact_details": {
	  "contact_details.mobile": {
		"phone.country_code": "+33",
		"phone.national_number": "98766543"
	  }
	}
  }

```

Graph after editing `quote`

```json
{
	"uid": "0x2a85",
	"quote": "Jupiter",
	"car": "Lambo"
  }

```

Update worked, but `user.contact_details` edge was disconnected 🤷‍♂️

* * *

Dgo go [documentation](https://godoc.org/github.com/dgraph-io/dgo#example-package--SetObject) says `While setting an object if a struct has a Uid then its properties in the graph are updated else a new node is created.`

I am providing code which:

1. Creates `User` with `quote` , `car` and Contact details. (All good)
2. Knowing UID of `User` I update `quote` . ( `quote` updated, `car` remains, however edge to Contact details disappeared)

```auto
package main

import (
	"context"
	"encoding/json"
	"fmt"
	"log"

	"github.com/dgraph-io/dgo/v200"
	"github.com/dgraph-io/dgo/v200/protos/api"
	"google.golang.org/grpc"
)

// User -
type User struct {
	UID string `json:"uid,omitempty"`
	DType []string `json:"dgraph.type,omitempty"`
	FavQuote string `json:"quote,omitempty"`
	FavCar string `json:"car,omitempty"`
	ContactDetails UserContactDetails `json:"user.contact_details,omitempty"`
}

// UserContactDetails -
type UserContactDetails struct {
	UID string `json:"uid,omitempty"`
	DType []string `json:"dgraph.type,omitempty"`
	Mobile PhoneNumber `json:"contact_details.mobile,omitempty"`
}

// PhoneNumber -
type PhoneNumber struct {
	UID string `json:"uid,omitempty"`
	DType []string `json:"dgraph.type,omitempty"`
	CountryCode string `json:"phone.country_code,omitempty"`
	NationalNumber string `json:"phone.national_number,omitempty"`
}

func main() {
	conn, err := grpc.Dial("localhost:9080", grpc.WithInsecure())
	if err != nil {
		log.Fatal(err)
	}
	defer conn.Close()
	dg := dgo.NewDgraphClient(api.NewDgraphClient(conn))

	u := User{
		UID: "_:newUser",
		DType: []string{"User"},
		FavQuote: "Moon",
		FavCar: "Lambo",
		ContactDetails: UserContactDetails{
			DType: []string{"ContactDetails"},
			Mobile: PhoneNumber{
				DType: []string{"PhoneNumber"},
				CountryCode: "+33",
				NationalNumber: "98766543",
			},
		},
	}

	op := &api.Operation{}
	op.Schema = `
		<phone.country_code>: string @index(exact) .
		<phone.national_number>: string @index(exact) .
		<quote>: string .
		<car>: string .

		type User {
			quote
			car
			user.contact_details: ContactDetails
		}

		type ContactDetails {
			contact_details.mobile: PhoneNumber
		}

		type PhoneNumber {
			phone.country_code
			phone.national_number
		}
	`

	ctx := context.Background()
	if err := dg.Alter(ctx, op); err != nil {
		log.Fatal(err)
	}

	// CREATING USER
	mu := &api.Mutation{
		CommitNow: true,
	}

	ub, err := json.Marshal(u)
	if err != nil {
		log.Fatal(err)
	}

	mu.SetJson = ub
	response, err := dg.NewTxn().Mutate(ctx, mu)
	if err != nil {
		log.Fatal(err)
	}

	uid := response.Uids["newUser"]
	fmt.Println("UID: " + uid)

	// User correctly created with all details and can be verified in Ratel

	// MODIFYING USER
	u = User{
		UID: uid,
		FavQuote: "Jupiter",
	}

	mu = &api.Mutation{
		CommitNow: true,
	}

	ub, err = json.Marshal(u)
	if err != nil {
		log.Fatal(err)
	}

	mu.SetJson = ub
	_, err = dg.NewTxn().Mutate(ctx, mu)
	if err != nil {
		log.Fatal(err)
	}

	// User updated `FavQuote`. "FavCar" remains however contact details edge from user have dissapeared !?
}

```

For querying data in Ratel I use

```auto
{
  u(func: uid(0x2a85)) {
    uid
    quote
    car
    user.contact_details {
      contact_details.mobile {
        phone.country_code
        phone.national_number
      }
    }
  }
}

```

Any ideas much appreciated!

---

<div class="post-metadata">

**Author:** ![Naman](https://yyz1.discourse-cdn.com/flex007/user_avatar/discuss.dgraph.io/naman/32/3498_2.png) [@Naman](https://discuss.dgraph.io/u/Naman)\
**Post date:** [July 7, 2020, 11:41am UTC](https://discuss.dgraph.io/t/updating-graph-using-struct-with-uid-makes-edges-disappear-dgo/7583/2 "2020-07-07T11:41:30Z")

</div>

Hi @AugustDev, [Welcome to Dgraph community](http://discuss.hypermode.com/t/whos-new-in-july-2020/7522).

> [@AugustDev](#):
>
> I have opened issue to this on dgo github, but I feel it will get more exposure here.

Yes, most of our community is active here and you may expect a quicker response here.

> [@AugustDev](#):
>
> The problem: updating a node causes loss of deeper nested edges using dgo.

This seems like a bug. The updates are failing for deeper nested mutations. Thanks for letting us know this. I have added the tag to the issue and our team will try to pick it up soon.

EDIT: As mentioned below by @AugustDev, it was a programming bug. 🙂

---

<div class="post-metadata">

**Author:** ![AugustDev](https://avatars.discourse-cdn.com/v4/letter/a/9e8a1a/32.png) [@AugustDev](https://discuss.dgraph.io/u/AugustDev)\
**Post date:** [July 7, 2020, 11:46am UTC](https://discuss.dgraph.io/t/updating-graph-using-struct-with-uid-makes-edges-disappear-dgo/7583/3 "2020-07-07T11:46:30Z")

</div>

Thanks for reply. However as someone pointed out on Slacks. The problem is because of the way go serializes structs. Every works as expected if I change `UserContactDetails` to `* UserContactDetails`, because empty elements are no longer initialized to default values and are simply omitted.