Simple date arithmetic 1

[teamakesmefart]

Hi All

How can I perform a simple addition on a Date variable in ObjectPAL? Surely procedure for such are built into Paradox?

What I want to do is add 1 year to a specified date. In a variation I may also want to find (1 year - 1 day) + specified date.

Obviously this would need to take into account whether a leap year is included in the calculable period.


Many thanks
Pete
Devon, UK

 

[TonyMcGuire]

For all things date related, see Rick Kelly's site.

I believe he has a calendar library, just not sure if there is a free version.

http://www.crooit.com

For the basic 'add a year', you could do something like:

newdate=date(
string(day(today()))+
"/"+
string(month(today()))+
"/"+
string(year(today())+1)
)

for the other, something like:

newdate-1

But what would you be meaning about finding a date-1, and then adding a specified date?

Tony McGuire

http://www.thedbcommunity.com

"It's not about having enough time. It's about priorities

 

[TonyMcGuire]

Transposed day/month in first post. MAN do I wish this forum had an edit function!

As to leapyear, I think you would just test for the current year being a leapyear and apply a day-1 to the newDate calculation if day(today())=29 and month(today())=2 :

dt=datetime()
if dt.isleapyear() then
if (month(dt)=2 and day(dt)=29) then
dy=28
endif
else
dy=day(dt)
endif

newdate=date(
string(month(dt)),+
"/"+
string(dy)+
"/"+
string(year(dt)+1)
)

If you need detailed calendaring/date calculations, get Rick's stuff.

Tony McGuire

http://www.thedbcommunity.com

"It's not about having enough time. It's about priorities

 

[SonOfTed]

Sometimes you can bypass the need to use ObjectPal simply by placing DATE calculations directly on Form and Report fields. I routinely use the following three items:

1. Calculating a person’s AGE as of today’s date. (Uses “Date of Birth” from Clients.DB).

iif([Clients.Date of Birth]>"",LongInt(number(Today()-[Clients.Date of Birth])/365.25),"")

Note: If you need to calculate the person’s age up through a specific date other than today, substitute “Today()” in the formula with: (A) a table date field name, or (B) a literal date. Example: “Date(“03/01/2005”)”


2. Calculating an employee’s years of service.

iif([History.Date Terminated]>"",round(number([History.Date Terminated] - [History.Date Hired])/365.25,1),iif([History.Date Hired] > 0,round(number(Today() - [History.Date Hired])/365.25,1),""))

Note: Partial years are converted and expressed as tenths (5.25 rounds to 5.3) as opposed to months (5 years and 3 months).


3. Sometimes I need to calculate years of Service as of a specific Cutoff Date given to me by management. In this case I use SQL to generate a Report table, and add text such as the following to the Select statement:

SELECT D.SSN, D.“Date Hired”, “12/31/2004" as CutoffDate, ...

My output table thus contains an extra Date Field column called CutoffDate. Each table row contains the constant date of 12/31/2004 in this column. I can then use:

CutoffDate - Date Hired

in report calculations.