如何确定需要从修改后的结构更新哪些数据库表列？

Question

The problem that I am facing is more of a code design rather than specifically go related. I am building a simple CRUD application and everything seems to go nice and easy except the updating part: I have a struct type as simple as:

type User struct {
   ID string
   Name string
   Password string
}

and an interface for data storage layer:

type Store interface {
    ...
    Update(user *User) error
    ...
}

The problem is that with most database drivers you can't just pass the whole struct instance and hope the their system knows which fields were modified, the whole document/row gets replaced. How should I track which fields were modified (so that I could update them in the storage layer accordingly)? Maybe pass all the fields I would like to modify to the Update function as a map of interface{}?

Answer 1

There are plenty of ways to achieve that. For example you can use setters to change the values.So you can keep track of updated fields. like so :

type User struct {
   ID string
   Name string
   Password string
   updateFields map[string]bool
}

func (u *User) SetName(name string) {
   u.Name = name
   updateFields["name"] = true
}

You can use more automated way by reflection.