I have a record with purchase date of 1/1/2015 10:30 AM and my system timezone is UTC.
If I change the database timezone to Eastern Time. Would the purchase date for the existing record be automatically converted to Eastern Time? For example from 1/1/2015 10:30AM to 1/1/2015 5:30PAM.
Is this a feature in Oracle?
Also, is there a way to figure out what timezone the pruchase date was recorded in?
Since your column's data type is TIMESTAMP, Oracle has no idea what time zone that timestamp is in. The data won't change if you change the time zone on either the client or the server. Similarly, there is no way to determine whether a particular value was intended to represent EST or MST or UTC. Obviously, if you know that all your data is recorded in UTC, you could write an update statement that converted the data to a different time zone.
If you care about the time zone and want to do time zone conversions, you'd really want to store the time zone along with the date in a TIMESTAMP WITH [LOCAL] TIME ZONE column. That makes it much easier to convert the data from one time zone to another. If you use a TIMESTAMP WITH LOCAL TIME ZONE, Oracle will automatically convert the data to the session's preferred time zone which allows different users to see the same data in their time zone without manipulating the data in the database.
Related
I have a field that contains time of order creation(order_time). Naturally, the best data type for that field is TIMESTAMP, but I want to create index and I'm not sure that TIMESTAMP index would be better than any numerical index. What's the best practice here?
I'm using oracle database
Always use the most appropriate data-type for the data:
If the data has date and time components and has a time-zone then use TIMESTAMP WITH TIME ZONE;
If the data has date and time components with fractional seconds and no time-zone then use TIMESTAMP;
If the data has date and time components with no fractional seconds and no time-zone then use DATE; and
If your data is an instant measured, for example, as the number of milliseconds (or seconds) since 1970-01-01 00:00:00 UTC and you almost entirely use it in its numeric form (i.e. you never, or very rarely, convert it to a human readable format such as YYYY-MM-DD HH:MI:SS.FF) then you may want to store it as a number. However, if you want to format it so it is readable or compare it to dates then you should prefer the TIMESTAMP (or DATE) data type.
Never use an inappropriate data-type for your column. The index performance between the different data-types should be mostly irrelevant and the overheads of converting from an inappropriate data-type to an appropriate one are likely to be a much more significant cost.
Currently my laravel config time zone is set to '+6:00' and MariaDB database time zone is set to SYSTEM, which is +6:00 as well. Now that I need to accommodate users from different time zones, I need to migrate all timestamp values to UTC to avoid any unintended time-related issues.
In MariaDB documentation it is stated that: https://mariadb.com/kb/en/timestamp/#time-zones
If a column uses the TIMESTAMP data type, then any inserted values are
converted from the session's time zone to Coordinated Universal Time
(UTC) when stored, and converted back to the session's time zone when
retrieved.
Now, this is where I am getting confused. What I understand from the above statement that I do not require to change anything in the database as timestamps are always stored in UTC no matter what is my session time zone is at the time of saving the data. Therefore, later on if I update my time zone to UTC in Laravel config, I should get the corresponding UTC value. But after changing the Time zone to UTC in Laravel config I am still getting the time in +6:00 format from eloquent model.
I think I am missing something here and would really appreciate any suggestion regarding this. Thanks in advance.
Is there any way to change the timezone from UTC to GMT+1 in the CRM database.
We have onpremise CRM. The issue we are facing like we have more than 100 reports running directly at crm database.
To convert all the dates to from UTC to GMT+1 will be time consuming and difficult. Also converting all the data time fields to date only is not possible.
As all the users belongs to a single timezone. Can we convert from UTC to GMT+1 in the database it self.
If we can convert what will be impact.
We cannot simply change that, as CRM product is designed to store all the datetime stamps as UTC in database. This actually helps to work/consume/transact by CRM users in multiple timezone without issues.
You should better prepare a wrapper function to convert to local timezone and use the stored values when reading or simply train the user to see it as it is, ie UTC
TL;DR - am I correct in thinking there is no way to determine the timezone used for a given record of a Date field when the server's time zone was changed at some point in the past?
A factory control system was designed to use UTC server (not Oracle) time so all Date columns were UTC. At some point in the past they changed the server time to local. Now years later, they would like the apps to display the correct date. Without knowing the date the change occurred, is there a way to SELECT so all Date records would be correct? I think I can either make the "modern" records correct or the pre-change records correct but not both unless I know when that happened. Since it was a Windows OS change, I don't think even the alert log would help assuming they haven't trimmed it at some point, but it's not easy to get any info or server access from them anyway. It had been 10g and is now 12c.
Correct. Oracle's DATE datatype is timezone agnostic. If you want to store timezone info in the database, use TIMESTAMP WITH TIMEZONE datatype.
I'm working on optimizing some functions in which I need to convert many timestamps to UTC. My need is to create a table with the columns as follows:
YEAR | TZ_NAME | Start of Daylight Savings | End of Daylight Savings
I can convert the timestamps easily using the from_tz function in oracle, however running this per timestamp isn't an option. Does anyone know how the oracle function works? I can't find any documentation that details where oracle keeps these daylight savings rules.
Any suggestions?
Thank you!
The time zone related information is stored in a file, as per: https://docs.oracle.com/cd/B19306_01/server.102/b14225/ch4datetime.htm#i1006667
The Oracle time zone files contain the valid time zone names. The
following information is also included for each time zone:
•Offset from Coordinated Universal Time (UTC)
•Transition times for Daylight Saving Time
•Abbreviations for standard time and Daylight Saving Time