英文:
How to save time in the database in Go when using GORM and Postgresql?
问题
我目前正在解析一个时间字符串并将其保存到数据库（PostgreSQL）中：
event.Time, _ := time.Parse("3:04 PM", "9:00 PM")
// event.Time 的值现在是：0000-01-01 21:00:00 +0000 UTC
db.Create(&event)
它给我返回了这个错误：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 的类型是 time.Time。
我还尝试将 event.Time 的类型设置为字符串，并在 PostgreSQL 中使用时间数据类型：
type Event struct {
Time string `gorm:"type:time"`
}
但是当从数据库中获取记录时，我遇到了错误：
sql: Scan error on column index 4: unsupported driver -> Scan pair: time.Time -> *string
英文:
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
答案1
得分: 6
进一步调查了这个问题。目前，GORM不支持除了timestamp with time zone之外的任何日期/时间类型。
从dialect_postgres.go中可以看到以下代码片段：
case reflect.Struct:
if _, ok := dataValue.Interface().(time.Time); ok {
sqlType = "timestamp with time zone"
}
所以基本上我看到你有两个选择：
要么在数据库中使用varchar(10)，在Go中使用string，并将其保存为"9:00 PM"（其中10是适合你的数字）
要么在数据库中使用timestamp with time zone，在Go中使用time.Time，并将日期部分格式化为一个固定的日期，例如01/01/1970：
time.Parse("2006-01-02 3:04PM", "1970-01-01 9:00PM")
在这种情况下，你将需要在展示时省略日期部分，但如果你计划按日期范围选择，这可能对你更好。
英文:
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.
答案2
得分: 2
你可以使用Gorm的sql标签来设置任意特定于数据库的类型。
type Event struct {
Time time.Time `sql:"type:timestamp without time zone"`
}
英文:
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"`
}
答案3
得分: 0
当在SQL中更新DATETIME字段时，Go字符串必须采用以下格式：time.Now().Format(time.RFC3339)。
英文:
When updating the DATETIME field in SQL, the Go string must be in this format: time.Now().Format(time.RFC3339).
答案4
得分: 0
从Postgres的角度来看，错误是因为没有0000年。如果你不指定日期，你可以将转换后的时间戳加1年，得到一个有效的Postgres时间戳'0001-01-01T21:00:00+00'。
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"
会得到相同的错误。作为演示，0001-01-01的前一天是：
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
英文:
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
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