How to upload a 0 value for not null in Go? - go

Question

I'm trying to upload data to a PSQL database and receive the following message:
error:
null value in column \"alarm\" violates not-null constraint
I've tracked it down to being that the alarm value is 0, not null, but 0... However Golang does not recognize this... Is there a way to get around this quirk?
type HsDatum struct {
ID int64
UUID uuid.UUID
HsAssociationID int64
Timestamp time.Time `sql:",notnull"`
Value int `sql:",notnull"`
Alarm int `sql:",notnull"`
CreatedAt time.Time
UpdatedAt time.Time
}
hsDatum := hsdata.HsDatum{
HsAssociationID: systemAssoc.ID,
Timestamp: startTime,
Value: 1,
Alarm: int(alarm), // 0 in this example
}
Added more information about the database logic:
func (h *HsDatum) BeforeInsert(db orm.DB) error {
timeNow := timeutil.TimeNow()
h.CreatedAt = timeNow
h.UpdatedAt = timeNow
// Manage distinct alarm table by checking for new value
// Note: HS data needs to arrive in chronological order by timestamp
needsUpdate := false
lastAlarm, err := hsdistinctalarms.GetHsDistinctAlarmByMostRecent(h.HsAssociationID)
var timeGap time.Duration
if database.IsEmptyTable(err) {
// No values so mark it
needsUpdate = true
} else if err == nil {
if lastAlarm.Alarm != h.Alarm {
// New value so mark it
needsUpdate = true
}
timeGap = h.Timestamp.Sub(lastAlarm.LastUpdated)
} else {
logrus.Errorf("Failed to get most recent distinct alarm: %s", err)
}
if needsUpdate {
// Create new alarm
newAlarm := hsdistinctalarms.HsDistinctAlarm{
HsAssociationID: h.HsAssociationID,
Timestamp: h.Timestamp,
Alarm: h.Alarm,
LastUpdated: h.Timestamp,
}
err = hsdistinctalarms.CreateHsDistinctAlarm(&newAlarm)
if err != nil {
logrus.Errorf("Failed to create hs distinct alarm: %s", err)
}
} else {
// Update timestamp
lastAlarm.LastUpdated = h.Timestamp
err = hsdistinctalarms.UpdateHsDistinctAlarm(&lastAlarm)
if err != nil {
logrus.Errorf("Failed to update hs distinct alarm: %s", err)
}
}
return nil
}
// CreateHsDatum creates the resource.
// It modifies the parameter in place and returns error information.
func CreateHsDatum(h *HsDatum) error {
return database.GetDB().Insert(h)
}

Answer 1

Option 1:
use pointers
e.g.
Alarm *int `sql:",notnull"`
...
Alarm: new(int) // init with zero value
or
Alarm: &alarm // set a pointer to the alarm variable (should be int)
Ugly? Yes.
Option 2:
use sql.NullInt32
e.g.
Alarm sql.NullInt32 `sql:",notnull"`
...
var a sql.NullInt32
if err := a.Scan(alarm); err != nil {
// handle error
}
...
Alarm: a
...