If the created_at field is not added, the db.Save() function will continue to perform insertion operations.

[polly3d]

GORM Playground Link

This is a fake URL to prevent this bug from being overlooked: go-gorm/playground#1

Description

The data model:

type User struct {
	ID           uint
	Name         string
}

Here are the steps to reproduce：

// Create first record
db.Create(&User{})

// Fetch the first record
var user *User
db.First(&user)

// Save record
user.Name = "jinzhu 2"
db.Save(&user)

// Save again with the same data
// It will throw an error: Error 1062 (23000): Duplicate entry '1' for key 'users.PRIMARY'
user.Name = "jinzhu 2"
db.Save(&user)

[github-actions]

The issue has been automatically marked as stale as it missing playground pull request link, which is important to help others understand your issue effectively and make sure the issue hasn't been fixed on latest master, checkout https://github.com/go-gorm/playground for details. it will be closed in 30 days if no further activity occurs. if you are asking question, please use the Question template, most likely your question already answered https://github.com/go-gorm/gorm/issues or described in the document https://gorm.io ✨ Search Before Asking ✨