type Passport struct {
    Uid         int64 `gorm:"primaryKey"`
    ...
}

i used dbMain.Set("gorm:table_options", "CHARSET=utf8mb4").AutoMigrate(new(Passport)) to created a table;

type Passport struct {
    Uid         int64 `gorm:"primaryKey"`
    Type        int   `gorm:"primaryKey"`
    ...
}

and then i changed my struct, wanna use AutoMigrate() to build composite primary key; but not working
btw gorm:"not null is useful