gORM belongs to association doesnt preload - go

Question

I am trying to make a relational database with gORM and I have a problem with the belongs to method that I can't get to work.
I am expecting to see the booking with the table it is related to but the booking just shows a table with nil values. and the TableID that it should refer to is also null.
I have created a small test which creates some data and prints out the results as json.
package main
import (
"encoding/json"
"fmt"
"gorm.io/driver/sqlite"
"gorm.io/gorm"
)
type User struct {
gorm.Model
Username string
Password string
Bookings []Booking `gorm:"polymorphic:Owner;"`
}
type Booking struct {
gorm.Model
TableID *int
Table Table
OwnerID uint
Time int
OwnerType string
}
type Table struct {
gorm.Model
Number int
Price int
}
func DatabaseConnection() *gorm.DB {
db, err := gorm.Open(sqlite.Open("./test.db"), &gorm.Config{})
if err != nil {
panic(err)
}
db.AutoMigrate(&Booking{})
db.AutoMigrate(&Table{})
db.AutoMigrate(&User{})
return db
}
func main() {
fmt.Println("creating stuff..")
createStuff()
fmt.Println("checking table..")
checkTable()
fmt.Println("checking booking..")
checkBooking()
fmt.Println("checking user..")
checkUser()
}
func checkTable() {
db := DatabaseConnection()
var table Table
db.First(&table)
u, _ := json.Marshal(&table)
fmt.Println(string(u))
}
func checkUser() {
db := DatabaseConnection()
var user User
db.First(&user)
db.Preload("Bookings.Table").Preload("Bookings").First(&user)
u, _ := json.Marshal(&user)
fmt.Println(string(u))
}
func checkBooking() {
db := DatabaseConnection()
var booking Booking
db.Preload("Table").First(&booking)
u, _ := json.Marshal(&booking)
fmt.Println(string(u))
}
func createStuff() {
db := DatabaseConnection()
tables := []Table{
{Number: 1, Price: 100},
{Number: 2, Price: 100},
{Number: 3, Price: 100},
{Number: 4, Price: 100},
{Number: 5, Price: 100},
{Number: 6, Price: 100},
{Number: 7, Price: 100},
}
user := User{
Username: "martin",
Password: "secret",
}
db.Create(&user)
db.Create(&tables)
booking := Booking{Time: 1234}
db.Model(&tables[0]).Association("Table").Append(
&booking,
)
db.Model(&user).Association("Bookings").Append(
&booking,
)
}
I get the following output from my test:
checking table..
{
"ID": 1,
"CreatedAt": "2021-12-06T14:56:27.169847346+01:00",
"UpdatedAt": "2021-12-06T14:56:27.169847346+01:00",
"DeletedAt": null,
"Number": 1,
"Price": 100
}
checking booking..
{
"ID": 1,
"CreatedAt": "2021-12-06T14:56:27.173323491+01:00",
"UpdatedAt": "2021-12-06T14:56:27.173323491+01:00",
"DeletedAt": null,
"TableID": null,
"Table": {
"ID": 0,
"CreatedAt": "0001-01-01T00:00:00Z",
"UpdatedAt": "0001-01-01T00:00:00Z",
"DeletedAt": null,
"Number": 0,
"Price": 0
},
"OwnerID": 1,
"Time": 1234,
"OwnerType": "users"
}
checking user..
{
"ID": 1,
"CreatedAt": "2021-12-06T14:56:27.166274122+01:00",
"UpdatedAt": "2021-12-06T14:56:27.17309057+01:00",
"DeletedAt": null,
"Username": "martin",
"Password": "secret",
"Bookings": [
{
"ID": 1,
"CreatedAt": "2021-12-06T14:56:27.173323491+01:00",
"UpdatedAt": "2021-12-06T14:56:27.173323491+01:00",
"DeletedAt": null,
"TableID": null,
"Table": {
"ID": 0,
"CreatedAt": "0001-01-01T00:00:00Z",
"UpdatedAt": "0001-01-01T00:00:00Z",
"DeletedAt": null,
"Number": 0,
"Price": 0
},
"OwnerID": 1,
"Time": 1234,
"OwnerType": "users"
}
]
}