The mongo adapter for MongoDB wraps the driver written by Gustavo Niemeyer.

Note > Please note that MongoDB:

  • Does not support transactions.
  • Does not support query builder.
  • Uses bson tags instead of db for mapping.


To use the package, you’ll need the bazaar version control system:

sudo apt-get install bzr -y

Once this requirement is met, you can use go get to download and install the adapter:

go get


Database Session

Import the package into your application:

// main.go
package main

import (

Define the mongo.ConnectionURL{} struct:

// ConnectionURL defines the DSN attributes.
type ConnectionURL struct {
  User     string
  Password string
  Host     string
  Database string
  Options  map[string]string

Pass the mongo.ConnectionURL value as argument to mongo.Open() so the mongo.Database session is created.

settings = mongo.ConnectionURL{

sess, err = mongo.Open(settings)

Note > The mongo.ParseURL() function is also provided in case you need to convert a DSN into a mongo.ConnectionURL:

// ParseURL parses s into a ConnectionURL struct.
mongo.ParseURL(s string) (ConnectionURL, error)

Common Database Operations

Once the connection is established, you can start performing operations on the database.


In the following example, a table named ‘birthday’ consisting of two columns (‘name’ and ‘born’) will be created. Before starting, the table will be searched in the database and, in the event it already exists, it will be removed. Then, three rows will be inserted into the table and checked for accuracy. To this end, the database will be queried and the matches (insertions) will be printed to standard output.

Note > The database operations described above refer to an advanced use of upper-db, hence they do not follow the exact same patterns of the tour and getting started page.

The rows are inserted into the birthday table. The database is queried for the insertions and is set to print them to standard output.

// example.go

package main

import (


var settings = mongo.ConnectionURL{
  Database:  `upperio_tests`,  // Database name
  Host:      ``,      // Server IP or name

type Birthday struct {
  // The 'name' column of the 'birthday' table
  // is mapped to the 'name' property.
  Name string `bson:"name"`
  // The 'born' column of the 'birthday' table
  // is mapped to the 'born' property.
  Born time.Time `bson:"born"`

func main() {

  // The database connection is attempted.
  sess, err := mongo.Open(settings)
  if err != nil {
    log.Fatalf("db.Open(): %q\n", err)
  defer sess.Close() // Closing the session is a good practice.

  // The 'birthday' table is referenced.
  birthdayCollection := sess.Collection("birthday")

  // Any rows that might have been added between the creation of
  // the table and the execution of this function are removed.
  err = birthdayCollection.Truncate()
  if err != nil {
    log.Fatalf("Truncate(): %q\n", err)

  // Three rows are inserted into the 'Birthday' table.
    Name: "Hayao Miyazaki",
    Born: time.Date(1941, time.January, 5, 0, 0, 0, 0, time.Local),

    Name: "Nobuo Uematsu",
    Born: time.Date(1959, time.March, 21, 0, 0, 0, 0, time.Local),

    Name: "Hironobu Sakaguchi",
    Born: time.Date(1962, time.November, 25, 0, 0, 0, 0, time.Local),

  // The database is queried for the rows inserted.
  res := birthdayCollection.Find()

  // The 'birthdays' variable is filled with the results found.
  var birthday []Birthday

  err = res.All(&birthday)
  if err != nil {
    log.Fatalf("res.All(): %q\n", err)

  // The 'birthdays' variable is printed to stdout.
  for _, birthday := range birthday {
      "%s was born in %s.\n",
      birthday.Born.Format("January 2, 2006"),

The Go file is compiled and executed using go run:

go run example.go

The output consists of three rows including names and birthdates:

Hayao Miyazaki was born in January 5, 1941.
Nobuo Uematsu was born in March 21, 1959.
Hironobu Sakaguchi was born in November 25, 1962.

Note > Click here to keep learning about different database operations that can be executed with upper-db.