running totals

[challenger]

my problem is that I have a an inventory of 20 engines that are being tested and i need to keep an accurate account of service hours between each overhaul . I have tried a number of time to work out a query ( i'm a new user of databases ) and cant get my list to update each engine with it the number of hrs . ie all 20 engines could run 24hrs ( or any other hrs ) but if one fails or there is a problem that engine starts at 0 hrs after an overhaul . this is repeated so eventually all 20 engines could show different running totals every time i put in 24 hrs or 16 hrs or whatever until it is overhauled . The number of hours inputed each session will be the same for each engine only it's hours between overhaul will change .


I have written all my database to take care of overhauls reports spares etc but this is really killing me . Has anyone any idea or seen any code that will do this for me .
Thx

[ItsMe]

Calculated data is not typically stored in tables. However, I believe you have a circumstance where it is necessary to store this sum.

The trick will be finding a Business Rule that allows for accurate updating of the DB. What I mean is, find some activity within operations that can translate to someone clicking a button to update the hrs. for an individual motor. I first though this could be done during an overhaul but, then you mentioned the hrs. are a daily cycle. So, identify something in operations that will allow for accurate recordkeeping.

I would start with separate tables and forms to create a Module, so to speak, specific for this function. Afterwards, you can decide how to merge it with your main DB.

Maybe you can assume 24 hrs. unless a motor has a hiccup. In this circumstance, a User can input the hiccup.

[burrina]

Summing the hrs should not be difficult. Using a RunSum would do the trick. If used in a form, try this:

=RunSum([Form],"PrimaryKey",[PrimaryKey],"FieldToSum")

If in a query, see this article: http://support.microsoft.com/kb/290136

HTH

[challenger]

thanks for the help but it seems this is not what I want sorry .

example

engine total hrs

1 52

2 118

3 84

4 0 ( just been overhauled)

these totals are made up by adding the hours to the respective engines . like so

session 1 24
session 2 7
session 3 32
session 4 29
session 5 23

I hope this makes it a bit clearer . there will be 2 tables i think such as session and running hours . If i can't figure this out i will fall back on an excel sheet to do the calcs which i don't really want to do

Thx

[burrina]

To get the results you seek as my understanding goes, then use a Group By Query and filter with your criteria. Using both tables, Engine and Session. Hard to say without seeing what you have. On your form of course you could use a Combo Box to filter by Session. Without specific table names, fields it is hard to figure out, at least for me.

[challenger]

Thanks for the help . i will potter around with this for a while . I didn't think it would be this hard to incrementally increase each number in a list by the same amount . maybe i should use the excel option
Thanks anyway