gorp更新不更新

Question

我有问题使用gorp更新postgresql数据库中的行,我成功地使用db.Exec运行更新,所有列都使用正确的信息更新,而gorp im只能更新非sql.Null*字段休息保持不变.

var db *sql.DB
var dbmap *gorp.DbMap

func getDB() (*sql.DB, *gorp.DbMap) {
    if db == nil {
        var err error
        db, err = sql.Open("postgres", "postgres://xxxxxxxx")
        db.SetMaxOpenConns(5)
        db.SetMaxIdleConns(0)
        dbmap = &gorp.DbMap{Db: db, Dialect: gorp.PostgresDialect{}}
        dbmap.AddTableWithName(WirelessNetwork{}, "network").SetKeys(true, "Id")
        if err != nil {
            log.Panic(err)
        }
    }

    return db, dbmap
}

type WirelessNetwork struct {
    Id        int             `db:"id"`
    Ssid      string          `db:"ssid"`
    Lat       sql.NullFloat64 `db:"lat"`
    Lon       sql.NullFloat64 `db:"lon"`
    Sec       sql.NullString  `db:"sec"`
    Bssid     sql.NullString  `db:"bssid"`
    Channel   sql.NullInt64   `db:"channel"`
    Found     bool            `db:"found"`
    Datefirst sql.NullString  `db:"datefirst"`
    Datelast  sql.NullString  `db:"datelast"`
}

npr := new(WirelessNetwork)
npr.Id = getNetworkId(ssid)
npr.Ssid = ssid
npr.Lat = dbProbes[index].Lat
npr.Lon = dbProbes[index].Lon
npr.Sec = dbProbes[index].Sec
npr.Bssid = dbProbes[index].Bssid
npr.Channel = dbProbes[index].Channel
npr.Found = dbProbes[index].Found
npr.Datefirst = dbProbes[index].Datefirst
npr.Datelast = dbProbes[index].Datelast
npr.Found = true

这有效

db, _ := getDB()
db.Exec("UPDATE network SET ssid=$1,lat=$2,lon=$3,sec=$4,channel=$5,found=$6,datefirst=$7,datelast=$8,bssid=$9 WHERE id=$10",
    npr.Ssid, npr.Lat.Float64, npr.Lon.Float64, npr.Sec.String, npr.Channel.Int64, npr.Found, npr.Datefirst.String, npr.Datelast.String, npr.Bssid.String, getNetworkId(ssid))

事实并非如此

func updateNetwork(n *WirelessNetwork) {
    _, dbmap := getDB()
    _, err := dbmap.Update(n)
   if err != nil {
        log.Fatal("updateNetwork - ", err)
   }
}

Answer 1

sql.Null*types是带有Valid布尔字段的结构,它告诉值是否为NULL.boolean的初始值为false,因此除非您明确验证数据,否则您将向数据库发送NULL.你没有告诉我们,dbProbes它是什么以及如何获取数据,但如果它是用类似的东西初始化的话

dbProbes[index].Lat = sql.NullFloat64{Float64: lat}

那么Valid仍然是假的,你需要手动验证你的数据:

dbProbes[index].Lat = sql.NullFloat64{Float64: lat, Valid: true}

或使用Scan方法:

err = dbProbes[index].Lat.Scan(lat)