How to save time in the database in Go when using GORM and Postgresql? - postgresql

Question

I'm currently parsing a time string and saving it to the db (Postgresql):
event.Time, _ := time.Parse("3:04 PM", "9:00 PM")
// value of event.Time now is: 0000-01-01 21:00:00 +0000 UTC
db.Create(&event)
It's giving me this error: pq: R:"DateTimeParseError" S:"ERROR" C:"22008" M:"date/time field value out of range: \"0000-01-01T21:00:00Z\"" F:"datetime.c" L:"3540"
event.Time⁠⁠⁠⁠'s type is time.Time.
I also tried setting event.Time's type to string and using time data type in postgresql:
type Event struct {
Time string `gorm:"type:time
}
But now I'm getting an error when fetching records in the db:
sql: Scan error on column index 4: unsupported driver -> Scan pair: time.Time -> *string

Answer 1

Investigated this issue further. Currently, there's no support in GORM for any Date/Time types except timestamp with time zone
See this part of code from dialect_postgres.go:
case reflect.Struct:
if _, ok := dataValue.Interface().(time.Time); ok {
sqlType = "timestamp with time zone"
}
So basically I see two options for you:
Either use varchar(10) in DB, and string in Go, an simply save it as "9:00 PM" (where 10 is some number that suits you)
Or use timestamp with time zone in DB, time.Time in Go, and format your date part as a constant date, 01/01/1970, for example:
time.Parse("2006-01-02 3:04PM", "1970-01-01 9:00PM")
In that case you'll have to omit the date part in your presentation, but if you plan to select by date range, that could work better for you.

Answer 2

You can set an arbitrary database-specific type with Gorm using sql tag
type Event struct {
Time time.Time `sql:"type:timestamp without time zone"`
}

Answer 3

When updating the DATETIME field in SQL, the Go string must be in this format: time.Now().Format(time.RFC3339).

Answer 4

From Postgres perspective the error stems from there being no year 0000. If you don't the date you may just be able to add 1 year to the converted timestamp giving '0001-01-01T21:00:00+00' which is a valid Postgres timestamp.
select '0000-01-01T21:00:00+00'::timestamptz at time zone 'UTC'
ERROR: date/time field value out of range: "0000-01-01T21:00:00+00"
Gives he same error. And just as a demonstration 1 day before 0001-01-01 gives:
select '0001-01-01T21:00:00+00'::timestamptz at time zone 'UTC' - interval '1 day' "day_before_1/1/1";
--day_before_1/1/1
--0001-12-31 21:00:00 BC