Working with Databases and International Date FormatsBy Darren Neimke
|Workaround for Non-English Countries|
Darren's article works wonders for international, English-speaking countries, like England, the
United States, Australia, and so on. However, in non-English speaking countries, the months of the
year are spelled differently and, hence, have different abbreviations. If you are from a non-English
speaking country you may wish to read Giuliano Sauro's article:
Using the ISO Date Format for International Dates.
If you've ever written a script that needs to
values in a database and you live outside of North America, then I'd nearly bet that
(like me) you've stayed up until midnight cursing the fact that all dates in SQL Server and
MS-Access are natively converted from US date format (
Why is that a problem I hear you ask? Simple, I'll tell you the answer to that question on
6/4/2001. Did you see that? No? OK then, what is 6/4/2001? Well if you are converting dates
mm/dd/yyyy format then the answer would be the 4th-Jun-2001. On the other
hand if you were converting dates using
dd/mm/yyyy format (as is the case in
Australia and the UK) then the answer would be 6th-Apr-2001. To see what I mean, if we copy
this code into an ASP page and run it:
the results are:
Now, before I explain how to remedy the problem, which, incidentally I already have anyway ;), first let's try to get a better understanding of what exactly is happening. Let's say that we produce an SQL String which looks strikingly like this:
The VBScripting engine interprets the
Date() function as a value, formats it
based on your Server/LCID settings, and then packages it all up as a *String* to send off to
the database's Query Engine. Once the Query Engine recieves this SQL statement it goes about
the job of Analyzing and Optimizing the query before passing it on the the Storage engine to
actually file the information away in the database.
To see why this is a problem we simply need to understand that all dates are stored in the database as numbers. In order to be able to store a date as a number, the date has to be converted to something other than the standard calendar format. The numeric representation of dates is called a Julian, or Serial, date. To do this, the date is converted to an offset from a fixed point in time.
In the case of Microsoft Access, this offset is 30th-Dec-1899, and all dates are stored as
the number of days since this date. Thus
7/7/93 is stored as
meaning 34,157 days since 30th-Dec-1899. Negative numbers represent dates prior to
Since adding 1 to a date represents 1 day or 24 hours, each hour is stored as
or 1/24 of a day. In Microsoft Access all times are stored as a fraction of a day. Each hour
is 1/24 of a day, each minute 1/1440, each second 1/86400. So 3:00 is stored as
(or 1/8 of a day), and 16:00 is stored as
0.666..., (or 2/3 of a day). Conversely,
0.2 represents 4:48 hours (1/5 of a day), and so on.
Therefore we see that the following snippet produces a result of
28/02/1900 6:00:00 AM
(assuming your LCID is set to display dates in
This is because 28th-Feb-1900 is 60 days added to 30-Dec-1899, and 06:00 AM is obviously a
.25) of the way through the day itself.
The general point here is that the underlying value stored in the database is simply
Now that we know how a database physically stores a date (answer: as a
we're ready for Part 2, in which we'll look at how
the Query Engine converts the SQL string containing the date (which is a string itself) into
the proper format.