invalid sql type (slice) for postgres - postgresql

Question

I want to AutoMigrate my Model but I get this error when running up:
invalid sql type (slice) for postgres
Here is my struct:
type Tracking struct {
ServerID int64
Tracks []map[string]interface{}
}
Im using gorm to work with the DB. (github.com/jinzhu/gorm)
The error comes from: AutoMigrate(&Tracking{})
Is there a solution to this?
Thanks already

Answer 1

The short answer is gorm and most SQL databases don't support slices as a data type. To work around this you need to tell gorm to set up a many to many relationship table.
Table1 <----> (Table1/Table2) <----> Table2
I was attempting the same thing, the gorm documentation advised the following and it worked for me:
type User struct {
gorm.Model
Languages []Language `gorm:"many2many:user_languages;"`
}
type Language struct {
gorm.Model
Name string
}
Taking a guess at yours I would do:
type Tracking struct {
ServerID int64
Tracks []Tracks `gorm:"many2many:tracking_tracks;"`
}
type Tracks struct {
gorm.Model
Text string
}
This sets up three tables as previously mentioned, your trackings table, your tracks table and a third one called tracking_tracks which will store the id to id relationship (many to many)
It's then important to note that for data you are querying from one table where there is a relationship with another table, you will need to Preload() those tables.
Using the gorm example you would do the following
var users []User
db.Preload("Languages").Find(&users)
Not doing this will return the users with the languages column empty.
If many to many doesn't suit you can try a has many or one to many relationship if that is more suitable https://gorm.io/docs/has_many.html