gorm primary key dont appear in database - database

Question

im a beginner in golang. when im using gorm:"primaryKey"
i dont see any field that use primary key
this is my model
type Orders struct {
OrderID uint64 `gorm:"primaryKey" json:"orderId"`
CustomerName string `json:"customerName"`
OrderedAt time.Time `json:"orderedAt" example:"2020-01-09T21:21:46+00:00"`
Items []Items `json:"items"`
}
type Items struct {
ItemID uint64 `gorm:"primaryKey" json:"lineItemId"`
Item_code string `json:"itemCode"`
Description string `json:"description"`
Quantity int `json:"quantity"`
}
which part do i wrong?
and do i need relational database for items field?

Answer 1

Lets be clear over here,
At first you need to declare a struct as a Model i.e by
type Anything struct {
gorm.Model
... (other fields)
}
And then in order to use Has Many relation you need to use the ID of the parent on the child i.e
type User struct {
gorm.Model
CreditCards []CreditCard
}
type CreditCard struct {
gorm.Model
Number string
UserID uint (like this over here.)
}
Please do kindly follow the docs GORM Docs

Answer 2

In the model Orders model has a hasMany relation to Items, but Items is missing the Key of Orders.
The db.AutoMigrate(&models.Orders{}, &models.Items{}) should be failing to create in this case for Order.Items, but the error is ignored.
Include OrdersID in Items struct to complete referential integrity because gorm expects default primary key/ foreign key as <StructName>ID so for Orders it will search OrdersID in Items
type Orders struct {
OrdersID uint64 `gorm:"primaryKey" json:"orderId"`
...
}
type Items struct {
OrdersID uint64
...
}
Suggestion, structs should be called Order and Item rather than Orders and Items thus the model becomes
type Order struct {
OrderID uint64 `gorm:"primaryKey" json:"orderId"`
CustomerName string `json:"customerName"`
OrderedAt time.Time `json:"orderedAt" example:"2020-01-09T21:21:46+00:00"`
Items []Item `json:"items"`
}
type Item struct {
ItemID uint64 `gorm:"primaryKey" json:"lineItemId"`
Item_code string `json:"itemCode"`
Description string `json:"description"`
Quantity int `json:"quantity"`
OrderID uint64
}