Gorm How to scan ignored field gorm:"-" ?

I have struct like this

type Menu struct {
    Name        string    `json:"name" gorm:"type:varchar(150);"`
    WebsiteName string    `json:"websiteName" gorm:"-"`
}

I want the WebsiteName to be able to scan but I do not want this field to be created in the Database. But when I add - the field does not get created in DB that's good but when I Scan(&menu) the field is not getting scanned.

How do I make this work ?

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Comment From: a631807682

Use permission tag.

WebsiteName  string `gorm:"<-:false;->:true"`

https://gorm.io/docs/models.html#Fields-Tags

Comment From: github-actions[bot]

Comment From: khanakia

WebsiteName string `gorm:"<-:false;->:true"`

Hi, it still creates a Column in the Database table website_name when I run gorm AutoMigrate command. It should not create a column in the database

Comment From: github-actions[bot]

Comment From: a631807682

I'm not sure what you mean, website_name is not a column in db, but should be able to scan? If website_name not a cloumn, what value needs to be scan into struct? Can you create a pull request to https://github.com/go-gorm/playground to describe it?

Comment From: github-actions[bot]

Comment From: khanakia

@a631807682 Please check I have provided the example code. Basically, the website name will come from a different table.


type Menu struct {
    Name        string    `json:"name" gorm:"type:varchar(150);"`
    WebsiteName string    `json:"websiteName" gorm:"-"`
}

var records []Menu
query := db.Table("menus as m").Select("m.*, w.name as website_name")
query.Joins("INNER JOIN websites w on w.id=m.website_id").Find(&records)

## This returns
[
    {
        "name": "Menu1",
        "websiteName": ""
    },

    {
        "name": "Menu2",
        "websiteName": ""
    }
]

Comment From: github-actions[bot]

Comment From: a631807682

@khanakia I haven't tried, but I think it might help you

WebsiteName  string `gorm:"<-:false;->;-:migration"`

<-:false no write permission, -> read permission, and -:migration ignore migration. https://github.com/go-gorm/gorm/pull/4028

Comment From: 260721735

i think you can use other struct for join select just like this

type Menu struct {
    Name        string    `json:"name" gorm:"type:varchar(150);"`
}
type JoinMenu struct {
    Menu        
    WebsiteName string    `json:"websiteName"`
}
var records []JoinMenu
query := db.Table("menus as m").Select("m.*, w.name as website_name")
query.Joins("INNER JOIN websites w on w.id=m.website_id").Find(&records)

model Menu use for insert,update,delete JoinMenu for complex queries with this design, database metadata model is safe when adding other complex queries

Comment From: github-actions[bot]

Comment From: Fakerr

@khanakia I haven't tried, but I think it might help you

WebsiteName string `gorm:"<-:false;->;-:migration"`

<-:false no write permission, -> read permission, and -:migration ignore migration. #4028

@a631807682 The problem with this solution is that, if later I want to query my model without the joint table, it throws an error:

type Menu struct {
    Name        string    `json:"name" gorm:"type:varchar(150);"`
    WebsiteName string    `json:"websiteName" gorm:"<-:false;->;-:migration"`
}

var user Menu
db.Where("id = ?", userID).First(&user)

returns:
`ERROR: column menu.website_name does not exist`

Comment From: a631807682

@Fakerr ~~I will fix it later~~ You define it to have read permissions, but you expect it to sometimes and sometimes not, so you should use Omit

Comment From: Fakerr

@a631807682 Ideally I would like to set the permission to not read and write gorm:"-", however sometimes I would like to add a field in my model that don't exist in the database but that I can scan a value into it. I created a separate ticket describing what I want to https://github.com/go-gorm/gorm/issues/5284

Comment From: mtt0

@khanakia I haven't tried, but I think it might help you

WebsiteName string `gorm:"<-:false;->;-:migration"`

<-:false no write permission, -> read permission, and -:migration ignore migration. #4028

It'w worked for me with gorm v1.23.5, thank you very much~

Comment From: khanakia

@mtt0 Yes I fixed it precisely like that already.