MongoDB find query with combination of $or and $and in golang - mongodb

Question

I want to get rows where:
{repair field has "ac" OR {repair is "tv" and phone field in range 1091-1100}}
I am trying the following query:
type M map[string]interface{}
conditions := M{"name": M{"$regex": "me"},
"$or": []M{M{"repair": M{"$eq": "ac"}},
"$and": []M{M{"repair": M{"$eq": "tv"}}, M{"phone": M{"$gte": 1091, "$lte": 1100}}}}}
fmt.Println(conditions)
err = c.Find(conditions).Sort("phone").Limit(20).All(&j)
However, I am getting a compile error:
index must be non-negative integer constant
cannot use []M literal (type []M) as type M in array or slice literal.

Answer 1

You're missing one M{ before "$and" and after you add that don't forget to add another closing brace }.
the good and the bad for comparison.

Answer 2

I don't know what driver your using, but I would probably do something like this..
package main
import (
"log"
"time"
mgo "gopkg.in/mgo.v2"
"gopkg.in/mgo.v2/bson"
)
const (
databaseString = ""
)
var db DataStore
type DataStore struct {
Session *mgo.Session
}
// database
func (ds *DataStore) ConnectToDB() {
mongoDBDialInfo := &mgo.DialInfo{
Addrs: []string{"localhost:27017"},
Timeout: 1 * time.Hour,
}
sess, err := mgo.DialWithInfo(mongoDBDialInfo)
if err != nil {
sess.Refresh()
panic(err)
}
sess.SetMode(mgo.Monotonic, true)
db.Session = sess
}
// J is the expected mongo return object
type J struct {
ID bson.ObjectId `bson:"_id,omitempty" json:"_id"`
// example data below
Status string `bson:"status" json:"status"`
}
func init() {
db.ConnectToDB()
}
func main() {
colectionString := ""
// probably best if this was a mapped mgo struct see above
// var j bson.M
var j J
// your orignal code
// I don't know why you are using $eq couldn't you just do bson.M{"repair":"ac"}, and bson.M{"repair":"tv"}
conditions := bson.M{"name": bson.M{"$regex": "me"},
"$or": []bson.M{
bson.M{"repair": bson.M{"$eq": "ac"}},
},
"$and": []bson.M{
bson.M{"repair": bson.M{"$eq": "tv"}},
bson.M{"phone": bson.M{"$gte": 1091, "$lte": 1100}},
}}
err := db.Session.DB(databaseString).C(colectionString).Find(conditions).Sort("phone").Limit(20).All(&j)
if err != nil {
log.Fatal(err)
}
}
I would probably also end up creating a separate package for the mongo connection stuff so that I can write wrapper functions around calls,
func FindItem(db *mgo.Session, id string) (data, error) {
defer sess.Close()
var res data //some data type struct
err := sess.DB("my db").C("my collection").Find(bson.M{"user": someID}).One(&data)
return data, err
}
then I'd be able to do things like this, which allow for concurrency
res, err := packagemain.FindItem(sess.Copy(), someID)
and your original code your you where missing } and ,. I suggest you use go vet or an ide which vets the code for you. Also, mgo is the mongo driver you probably what you want to be using if you're not using it already.