model 层实现问题

"github.com/astaxie/beedb"
"github.com/ziutek/mymysql/godrv"

package models
import (
"time"
"github.com/astaxie/beego"
"github.com/astaxie/beego/orm"
_ "github.com/go-sql-driver/mysql"
)
//Blog
type Blog struct {
Id      int `PK`
Title   string
Content string
Created time.Time
}
//
func init() {
//register database with drivermode
orm.RegisterDataBase("default", "mysql", "username:password@tcp(Ip:port)/databasename?charset=utf8", 30)
//register table
orm.RegisterModel(new(Blog))
//create table
orm.RunSyncdb("default", false, true)
//set the explort file of log
beego.SetLogger("file", `{"filename":"logs/test.log"}`)
}
//
func GetLink() orm.Ormer {
o := orm.NewOrm()
return o
}
//
func GetAll() (blogs []Blog) {
db := GetLink()
db.QueryTable("Blog").All(&blogs)
return
}
//
func GetBlog(id int) (blog Blog) {
db := GetLink()
blog.Id = id
db.Read(&blog)
return
}
//
func SaveBlog(blog Blog) (bg Blog) {
db := GetLink()
f := Blog{Id: blog.Id}
if db.Read(&f) == nil {
    _, err := db.Update(&blog)
    if err != nil {
        beego.Error("Update error:", err)
    } else {
        beego.Informational("update success!")
    }
} else {
    db.Insert(&blog)
    beego.Informational("Insert success!")
}
return bg
}
//
func DelBlog(blog Blog) {
db := GetLink()
db.Delete(&blog)
return
}