Gorm Failed to auto migrate, but got error Error 1170: BLOB/TEXT column 'user_refer' used in key specification without a key length

Description

when i used User.Name for primary_key,call AutoMigrate() will got error,like this:

2020/09/03 15:05:30 /Users/mybook/go/src/demo/src/db/connect.go:30 Error 1170: BLOB/TEXT column 'user_refer' used in key specification without a key length
[0.417ms] [rows:0] CREATE TABLE `credit_cards` (`number` longtext,`user_refer` longtext,CONSTRAINT `fk_users_credit_cards` FOREIGN KEY (`user_refer`) REFERENCES `users`(`name`))
2020/09/03 15:05:30 Failed to auto migrate, but got error Error 1170: BLOB/TEXT column 'user_refer' used in key specification without a key length

my models :

type User struct {
    Name string `gorm:"primary_key"`
    CreditCards []CreditCard `gorm:"foreignKey:UserRefer"`
}

type CreditCard struct {
    Number    string
    UserRefer string
}

ENV

gorm.io/driver/mysql v1.0.1
gorm.io/gorm v1.20.0

go version go1.14.4 darwin/amd64

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Comment From: jinzhu

set size for field UserRefer, e.g:

type CreditCard struct {
    Number    string
    UserRefer string `gorm:"size:191"`
}

Comment From: diluga

set size for field UserRefer, e.g:

go type CreditCard struct { Number string UserRefer string `gorm:"size:191"` }

thx!

Comment From: justincletus

set size for field UserRefer, e.g:

go type CreditCard struct { Number string UserRefer string `gorm:"size:191"` }

@diluga Thanks this works for me too

Comment From: pomozoff

What is the difference with the length attribute?

Comment From: mafif21

go size:191

TYSM bro its work for me ✨