How to define []string in Gorm Model

[Urento]

I have been trying to define a []string in a Gorm Model looking like this

type Shoppinglist struct {
	Model

	Title        string
	Items        []string
	Owner        string
	Participants []string
}

My Model struct looks like this:

type Model struct {
	ID         int `gorm:"private_key" json:"id"`
	CreatedOn  int `gorm:"autoCreateTime" json:"created_on"`
	ModifiedOn int `gorm:"autoUpdateTime:milli" json:"modified_on"`
}

When I try to AutoMigrate it like this:
db.AutoMigrate(&Shoppinglist{})

I get an error:

unsupported data type: &[]

And I think its the []string because I can't find it in an example in the documentation. I would highly appreciate any help!

The document you expected this should be explained

I'd expect it to be explained in https://gorm.io/docs/models.html

Expected answer

I want to know if something is wrong with my Model and if, what?
E.g. is it the []string or is it something completly different. And if it is the []string how do I store an Array?

[Urento]

I also got this error

failed to parse value &models.Shoppinglist{Model:models.Model{ID:0, CreatedOn:0, ModifiedOn:0}, Title:"", Items:[]string(nil), Owner:"", Participants:[]string(nil)}, got error unsupported data type: &[]

[Urento]

This is the test i wrote (I am very new to Go btw):

func TestCreate(t *testing.T) {
	Setup()

	id := rand.Intn(10000)
	title := StringWithCharset(20)
	items := []string{StringWithCharset(45), StringWithCharset(45), StringWithCharset(45), StringWithCharset(45)}
	owner := StringWithCharset(30)
	participants := []string{StringWithCharset(45), StringWithCharset(45), StringWithCharset(45), StringWithCharset(45)}
	shoppinglist := Shoppinglist{
		ID:           id,
		Title:        title,
		Items:        items,
		Owner:        owner,
		Participants: participants,
	}
	err := shoppinglist.Create()
	if err != nil {
		fmt.Println(err.Error())
		t.Errorf("Failed to create shoppinglist")
	}

	list := Shoppinglist{ID: id}
	exists, err := list.ExistsByID()
	if err != nil || !exists {
		t.Errorf("Shoppinglist did not get created")
	}

	l, err := list.GetList()
	if err != nil {
		t.Errorf("Shoppinglist not found")
	}

	if l.ID != id || !testEq(l.Items, items) || l.Owner != owner || !testEq(l.Participants, participants) || l.Title != title {
		t.Errorf("Values weren't correct ")
	}

	err = list.Delete()
	if err != nil {
		t.Errorf("Unable to delete the list")
	}

}

The Error gets thrown from by the Create Method

func (s *Shoppinglist) Create() error {
	shoppinglist := map[string]interface{}{
		"id":           s.ID,
		"title":        s.Title,
		"items":        s.Items,
		"owner":        s.Owner,
		"participants": s.Participants,
	}

	if err := models.CreateList(shoppinglist); err != nil {
		log.Fatal(err.Error())
		return err
	}

	return nil
}

func CreateList(data map[string]interface{}) error {
	list := Shoppinglist{
		Title:        data["title"].(string),
		Items:        data["items"].([]string),
		Owner:        data["owner"].(string),
		Participants: data["participants"].([]string),
	}
	if err := db.Create(&list).Error; err != nil {
		return err
	}
	return nil
}

[Urento]

Got it to work when I changed the string[] to pq.StringArray gorm:"type:text[]"

[mike-lloyd03]

Got it to work when I changed the string[] to pq.StringArray gorm:"type:text[]"

Is this documented anywhere? Spent a lot of time trying to find this answer.

[zbysir]

Got it to work when I changed the string[] to pq.StringArray gorm:"type:text[]"

Is this documented anywhere? Spent a lot of time trying to find this answer.

Me too, the docs are a bit rotten. It would be better if the error message was accompanied by suggestions, such as 'maybe you need to add type definition to the tag'

[jinzhu]

Got it to work when I changed the string[] to pq.StringArray gorm:"type:text[]"

Is this documented anywhere? Spent a lot of time trying to find this answer.

https://gorm.io/docs/serializer.html

[zbysir]

Got it to work when I changed the string[] to pq.StringArray gorm:"type:text[]"

Is this documented anywhere? Spent a lot of time trying to find this answer.

https://gorm.io/docs/serializer.html

Hi~ @jinzhu, Guess which one of them works?

1. pq.StringArray

type Post struct {
  Title  string
  Tags   pq.StringArray
}

2. pq.StringArray and type

type Post struct {
  Title  string
  Tags   pq.StringArray `gorm:"type:text[]"`
}

3. []string and type

type Post struct {
  Title  string
  Tags   []string `gorm:"type:text[]"`
}

4. []string and serializer

type Post struct {
  Title  string
  Tags   []string `gorm:"serializer:json"`
}

5. []string and serializer and type

type Post struct {
  Title  string
  Tags   []string `gorm:"type:text[]; serializer:json"`
}

If they both work, which one is better to use?