golang mongodb (mgo) is not inserting docs

问题

Im having issues with persisting a golang struct in mongodb using mgo.

type AN_Track_Log struct {
    Id                       bson.ObjectId `bson:"_id,omitempty"`
    user_session_id_str      string       `bson:"user_session_id_str"`

    googleanaly_pixel_id_str string `bson:"googleanaly_pixel_id_str"`
    perfaud_pixel_id_str     string `bson:"perfaud_pixel_id_str"`
    site_id_str              string `bson:"site_id_str"`
    metric_str               string `bson:"metric_str"`
    value_str                string `bson:"value_str"`
    event_str                string `bson:"event_str"`
    location_id_str          string `bson:"location_id_str"`
    referer_str              string `bson:"referer_str"`
    track_origin_str         string `bson:"track_origin_str"`
    fingerprint_str          string `bson:"fingerprint_str"`
    ...
}

p_track_log.Id = bson.NewObjectId()
err := p_mongodb_coll.Insert(&p_track_log)

the problem is that when the Insert() call completes, the only thing thats persisted in the DB is an empty doc

{u'_id': ObjectId('561809d20037873154000003')}

I check that the struct fields are indeed set, and not empty. Any ideas as to why this is happening. Hints are appreciated :) thank you

回答1:

You need to export the fields by starting the field name with a capital letter.

type AN_Track_Log struct {
  Id                       bson.ObjectId `bson:"_id,omitempty"`
  User_session_id_str      string       `bson:"user_session_id_str"`

  Googleanaly_pixel_id_str string `bson:"googleanaly_pixel_id_str"`
  ...
}

来源：https://stackoverflow.com/questions/33045404/golang-mongodb-mgo-is-not-inserting-docs