模型没有主键

Question

I'm using https://github.com/go-pg/pg for my PostegreSQL database and Go. I'm trying to get the value of a table Settings that has the column site_name but for some reason it is giving me the error panic: model=Settings does not have primary keys

package mypackage

import (
    "database"
)

type Settings struct {
    SiteName string
}

func Get() string {
    var name Settings

    err := Db.Model(&name).First()
    if err != nil {
        panic(err)
    }

    return name.SiteName
}

I don't have the experience to really understand what's going on here or how to fix it. Any solutions? Thanks!

Example (FirstRow): https://godoc.org/github.com/go-pg/pg#DB.Select

Answer 1

The ORM requires you to define pks, so you will have to add it to the struct as well as your db table.

https://github.com/go-pg/pg/blob/master/orm/query.go#L558 https://github.com/go-pg/pg/blob/d4fc7afde3ee9d0a780f9c67daf8a8a3bfd84060/orm/table.go#L124

So add an Id field to your struct

type Settings struct {
    Id       int64
    SiteName string
}

If you want to use an ORM you have to play by it's rules :) If you want more control try using sqlx instead