Two interesting test cases?

The first output is missing “Cars” and your first delete didn’t happen. You need to “restore” the database to its original state…

jchiu@jchiudesktop:~/dgraph$ curl localhost:8080/query -XPOST -d '{
>   debug(_uid_: 0xc1cee22c7ab32e68 ) {
>       type.object.name.en
>     }
>   }
> }' | python -m json.tool
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   253  100   176  100    77  90395  39548 --:--:-- --:--:-- --:--:--  171k
{
    "debug": {
        "_uid_": "0xc1cee22c7ab32e68",
        "type.object.name.en": "Cars"
    },
    "server_latency": {
        "json": "37.827\u00b5s",
        "parsing": "37.729\u00b5s",
        "processing": "246.729\u00b5s",
        "total": "323.682\u00b5s"
    }
}
jchiu@jchiudesktop:~/dgraph$ 
jchiu@jchiudesktop:~/dgraph$ curl localhost:8080/query -XPOST -d 'mutation {
>   delete {
>      _uid_:0xc1cee22c7ab32e68 <type.object.name.en> "Cars" .
>   }
> }' | python -m json.tool
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   123  100    35  100    88   5634  14166 --:--:-- --:--:-- --:--:-- 17600
{
    "code": "ErrorOk",
    "message": "Done"
}
jchiu@jchiudesktop:~/dgraph$ 
jchiu@jchiudesktop:~/dgraph$ curl localhost:8080/query -XPOST -d '{
>   debug(_uid_: 0xc1cee22c7ab32e68 ) {
>       type.object.name.en
>     }
>   }
> }' | python -m json.tool
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   222  100   145  100    77   121k  66037 --:--:-- --:--:-- --:--:--  141k
{
    "debug": {
        "_uid_": "0xc1cee22c7ab32e68"
    },
    "server_latency": {
        "json": "18.477\u00b5s",
        "parsing": "48.25\u00b5s",
        "processing": "45.528\u00b5s",
        "total": "114.021\u00b5s"
    }
}
jchiu@jchiudesktop:~/dgraph$ 
jchiu@jchiudesktop:~/dgraph$ curl localhost:8080/query -XPOST -d 'mutation {
>   set {
>      _uid_:0xc1cee22c7ab32e68 <type.object.name.en> "newcar3" .
>   }
> }' | python -m json.tool
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   123  100    35  100    88   5791  14562 --:--:-- --:--:-- --:--:-- 17600
{
    "code": "ErrorOk",
    "message": "Done"
}
jchiu@jchiudesktop:~/dgraph$ 
jchiu@jchiudesktop:~/dgraph$ curl localhost:8080/query -XPOST -d '{
>   debug(_uid_: 0xc1cee22c7ab32e68 ) {
>       type.object.name.en
>     }
>   }
> }' | python -m json.tool
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   253  100   176  100    77   136k  61354 --:--:-- --:--:-- --:--:--  171k
{
    "debug": {
        "_uid_": "0xc1cee22c7ab32e68",
        "type.object.name.en": "newcar3"
    },
    "server_latency": {
        "json": "23.212\u00b5s",
        "parsing": "44.5\u00b5s",
        "processing": "52.675\u00b5s",
        "total": "121.919\u00b5s"
    }
}
jchiu@jchiudesktop:~/dgraph$ 
jchiu@jchiudesktop:~/dgraph$ curl localhost:8080/query -XPOST -d 'mutation {
>   delete {
>      _uid_:0xc1cee22c7ab32e68 <type.object.name.en> "newcar3" .
>   }
> }' | python -m json.tool
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   126  100    35  100    91   5865  15250 --:--:-- --:--:-- --:--:-- 18200
{
    "code": "ErrorOk",
    "message": "Done"
}

jchiu@jchiudesktop:~/dgraph$ 
jchiu@jchiudesktop:~/dgraph$ curl localhost:8080/query -XPOST -d '{
>   debug(_uid_: 0xc1cee22c7ab32e68 ) {
>       type.object.name.en
>     }
>   }
> }' | python -m json.tool
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   257  100   180  100    77  39911  17073 --:--:-- --:--:-- --:--:--  175k
{
    "debug": {
        "_uid_": "0xc1cee22c7ab32e68",
        "type.object.name.en": "newcar3"
    },
    "server_latency": {
        "json": "68.198\u00b5s",
        "parsing": "105.212\u00b5s",
        "processing": "154.177\u00b5s",
        "total": "331.647\u00b5s"
    }
}