The LA Fox Developer Newsletter

August 1999

Take Care with Dates and Times

Don’t let date and datetime anomalies catch you out.

Visual FoxPro’s array of date and datetime functions normally work flawlessly ... but the results are not always what you might expect. For instance, assigning a “blank” date value to a variable, like this: a = (0/0/0) will correctly create a date variable. But assigning a blank datetime does not produce datetime variable. Thus: b = (0/0/0 0:00AM) makes b a date, not a datetime as you might have thought

Curiously, the following code does create an empty datetime:

b (/:)

Another unexpected behavior is that this construct: (:} translates to: 12/30/1899 12:00:00AM

Migration

If you are migrating to VFP from FoxPro 2.x, be aware that the former is stricter than the latter in its use of date separators. For example, CTOD(”11298”) is valid in 2.x, regardless of SET SEPARATOR, but it generates an invalid date in Visual FoxPro.

Year 2000 issues

Visual FoxPre is, for the most part, Year 2000 compliant .. but care is needed. To demonstrate, let’s look ahead ten years from the day this article was written:

SET CENTURY ON

dAnrdv = (12/30/07) && ten years from 12/30/97

Now subtract ten years from that date, like this:

? GOMONTH(dAnniv,-120)

If you are using VFP 5 or earlier, the result will be 12/30/1 897 a hundred years earlier than you might have expected.

Thars not a bug. Ihe point is that, when you specify a two-digit year (in VFP 5 or earlier), the century digits are always taken as 19—even if CENTURY is on, and regardless of the system date. If, during 1998 and 1999, your users will be entering forward dates for the next century — contract expiration dates, for instance — you might want to amend your forms to allow the full four-digit year to be entered.

By putting the following line of code at the start of your application: SET CENTURY TO 20 you ensure that the century digits in a two-digit year are always 20.

Going further, this line of code:

SET CENTURY TO 19 ROLLOVER 45

(Con't, next column)

Job Opportunites

I’ve got a couple of customers in need of FoxPro expertise. Both in the valley: Glendale & North Hollywood. I’ve gota ‘world class’ Foxpro programmer who is out of commisron for about a month, sick. One of his jobs requires a ‘reservation system’ interlaced with SBTs vfp5o ported package. This is an immediate need and will serve as a ‘trial balloon’ so to speak. We normally do the billing, initial analysis, assist with customer interface and skim some profit off the top though other options are available.

Another customer is going into full beta on our newly developed ‘Web Wan”; multiple branch offices access business system at home office via the web. Comprised of home office ‘server’ and branch ‘client’ applications in VFP5 and 6(?) using ‘Web connect’ by Rick Strawl. They are coming up with little bugs that’ll need fixing. Let me know if you have anyone interested who has the time.

Jim Shannon at JES Computer Systems (661) 297-2249, (888) Fox-Pros <mailto:JimShannon@softwarecustom.cbm>

Web: <<http://www. pacificnet.net/~jimsha>> & <http:// www.software-custom.com>

I am in need of a consultant in the Los Angeles area experienced in Foxpro Visual. The job would be more as an insructor since we are already familiar with FoxPro for Windows, but need some customization modifications to a an application from Satan in order to run their Mail Room Toolkit I have a small bulk mail business which provides automated mail savings to our customers. Please contact Patsy Bellah at Bellah Business Support Services, (310) 840-2957, or e-mail bellah@caprica.com.

Dates and Times (Con't from prev. column)

says that the century digits in a two-digit year will be 19 if the last two digits are 45 or higher, otherwise the century digits will be 20. In many cases, adding this code will be the only action you need to take to allow your users to go on entering just the last two digits of the year.

By the way, these two forms of SET CENTURY were new to VFP 5.0. They won’t work with earlier versions.

In VFP 6.0, the rollover is established by default, with the pivot year set to the current year digits plus 50. So, in 1999, a two- dig it year will be interpreted as being in the range 1950 to 2049. Then, in each following year, the range will move forward one year.

(Con't, page 8)

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