save should be idempotent

[black-06]

• Do only one thing
• Non breaking API changes
• Tested

What did this pull request do?

Save should be idempotent. #6139 #6134

When call Save twice with the same object, Save should not raise an error.

User Case Description

var company Company
DB.Frist(&company)

DB.Save(&company)
DB.Save(&company) // should not create new record or rasise an error.
DB.Save(&company) // should not create new record or rasise an error.

[monoflash]

MySQL MariaDB database, same problem.
Save() does not work from version 1.24.6 to latest.
The latest version in which Save() works is v1.24.5.

[jhemmmm]

I stopped using save as they keep having race data problems. The save should only update the column that has been changed.

[black-06]

I stopped using save as they keep having race data problems. The save should only update the column that has been changed.

Not, See Save doc

Save will save all fields when performing the Updating SQL

[jhemmmm]

I'm aware.