Unable to create Associations via golang orm library - go

Question

I've been trying to use the Associations feature in golang orm (https://github.com/jinzhu/gorm/), and am unable to create a pretty simple association.
In the example below, the user table contains data, but email table does not.
I've tried a bunch of things and I'm probably missing something basic, but have been unable to find the right answer in github/stackoverflow.
Code :
package main
import (
"database/sql"
"log"
"github.com/jinzhu/gorm"
"github.com/mattn/go-sqlite3"
)
var db gorm.DB
type User struct {
Name string
Mail Email
}
type Email struct {
Address string
}
//Initialize DB .
func InitDB() {
var DB_DRIVER string
sql.Register(DB_DRIVER, &sqlite3.SQLiteDriver{})
log.Printf("Initializing Database with ", DB_DRIVER)
dbSql, _ := sql.Open(DB_DRIVER, "simple-sqlite")
var err error
db, err = gorm.Open("sqlite3", dbSql)
if err != nil {
log.Fatalf("Got error when connecting to the database, the error is '%v'", err)
}
db.LogMode(true)
// Then you could invoke `*sql.DB`'s functions with it
db.DB().Ping()
db.DB().SetMaxIdleConns(10)
db.DB().SetMaxOpenConns(100)
// Disable table name's pluralization
db.SingularTable(true)
}
func InitSchema() {
db.CreateTable(&User{}, &Email{})
}
func DoStuff() {
user := User{Name: "Jinzhu", Mail: Email{Address: "hello#hello.com"}}
db.Create(&user)
}
func main() {
InitDB()
InitSchema()
DoStuff()
}
go run main.go prints the following output
2015/09/30 17:25:04 Initializing Database with %!(EXTRA string=)
[2015-09-30 17:25:04] [3.21ms] CREATE TABLE "user" ("name" varchar(255))
[2015-09-30 17:25:04] [4.01ms] CREATE TABLE "email" ("address" varchar(255) )
[2015-09-30 17:25:04] [0.54ms] INSERT INTO "user" ("name") VALUES ('Jinzhu')
Not sure what I'm missing here - appreciate any response!

Answer 1

You're missing your primary/foreign key references for each of your models, here's the updated code:
package main
import (
"database/sql"
"log"
"github.com/jinzhu/gorm"
"github.com/mattn/go-sqlite3"
)
var db gorm.DB
type User struct {
ID uint `gorm:"primary_key"`
Name string
Mail Email
MailID sql.NullInt64
}
type Email struct {
ID uint `gorm:"primary_key"`
Address string
}
//Initialize DB .
func InitDB() {
var DB_DRIVER string
sql.Register(DB_DRIVER, &sqlite3.SQLiteDriver{})
log.Printf("Initializing Database with ", DB_DRIVER)
dbSql, _ := sql.Open(DB_DRIVER, "simple-sqlite")
var err error
db, err = gorm.Open("sqlite3", dbSql)
if err != nil {
log.Fatalf("Got error when connecting to the database, the error is '%v'", err)
}
db.LogMode(true)
// Then you could invoke `*sql.DB`'s functions with it
db.DB().Ping()
db.DB().SetMaxIdleConns(10)
db.DB().SetMaxOpenConns(100)
// Disable table name's pluralization
db.SingularTable(true)
}
func InitSchema() {
db.CreateTable(&User{}, &Email{})
}
func DoStuff() {
user := User{Name: "Jinzhu", Mail: Email{Address: "hello#hello.com"}}
db.Create(&user)
}
func main() {
InitDB()
InitSchema()
DoStuff()
}
notice the primary keys on the User and Email structs as well as the foreign key reference on User