golang-> gorm：如何在mysql中将sql.NullInt64用作int（10）？

Question

type Contact struct {
  gorm.Model
  PersonID sql.NullInt64
}

type Person struct {
  gorm.Model
}

I am trying to use gorm with mysql in the previuos code but I have the following problem:

I want:

• Use sql.NullInt64 to work easily with null values.
• Use the base model definition gorm.Model, including fields ID, CreatedAt, UpdatedAt, DeletedAt.
• Add a constraint Db.Model(&models.Contact{}).AddForeignKey.

My problem:

• Person.ID become "int(10)" in mysql.
• Contact.PersonID become "bigint(20)"
• MySql need the same type for pk and fk.

Some body can help me to solve this?

Answer 1

The "magic" on gorm.Model is only the name of the fields, any struct with these fields look like this according to the gorm documentation, at the end of Conventions

For example: Save records having UpdatedAt field will set it to current time.

Or

Delete records having DeletedAt field, it won't be deleted from database, but only set field DeletedAt's value to current time, and the record is not findable when querying, refer Soft Delete

So solve the issue is very easy, this is the code for my case:

package models

import "time"

type Model struct {
    ID        uint `gorm:"primary_key;type:bigint(20) not null auto_increment"`
    CreatedAt time.Time
    UpdatedAt time.Time
    DeletedAt *time.Time `sql:"index"`
}

So, now I only need use it as base model :)