Mathematical Calculations in a form linked back to a table
in [General]
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From: Graeme on 26 Mar 2010 13:52 Hello I palnning on implementing calculation between two fields, and the result within another field. Suppose I have three fields called A B and C respectively. In the form I plan on Inputing a value for[A] and Inputing a value for [B]. Now, Field [C] will calculate [A]-[B]. When filed [C] is calculated, it is not in the table, like A and B are. I would like to know how to solve this problem. --- frmsrcurl: http://msgroups.net/microsoft.public.access/
From: Jeff Boyce on 26 Mar 2010 14:37 It is rarely necessary to store a calculated value in a table in Access. Much more commonly, a form (as you are using) or a query is used to do the calculation "on the fly", as it were. Since the values in either [A] or [B] could change, what about the idea of adding code to the AfterUpdate event of BOTH of those controls, recalculating the displayed (but not stored) value for the control [C]? Regards Jeff Boyce Microsoft Access MVP -- Disclaimer: This author may have received products and services mentioned in this post. Mention and/or description of a product or service herein does not constitute endorsement thereof. Any code or pseudocode included in this post is offered "as is", with no guarantee as to suitability. You can thank the FTC of the USA for making this disclaimer possible/necessary. "Graeme" <user(a)msgroups.net/> wrote in message news:%23xbSQ0QzKHA.5936(a)TK2MSFTNGP04.phx.gbl... > Hello > I palnning on implementing calculation between two fields, and the result > within another field. Suppose I have three fields called A B and C > respectively. In the form I plan on Inputing a value for[A] and Inputing a > value for [B]. Now, Field [C] will calculate [A]-[B]. When filed [C] is > calculated, it is not in the table, like A and B are. I would like to know > how to solve this problem. > > --- > frmsrcurl: http://msgroups.net/microsoft.public.access/
From: KenSheridan via AccessMonster.com on 26 Mar 2010 14:38 There is no problem; the value in C is a computed value derived from the values of A and B, and can be computed whenever required in a computed column in a query or a computed control in a form or report. To store the computed value in a column I the table would introduce redundancy and leave the table at risk of inconsistent data. Delete the C column from the table and compute the value whenever necessary; that way it is guaranteed that there will be no inconsistency between the computed value and the values from which it is derived. Ken Sheridan Stafford, England Graeme wrote: >Hell >I palnning on implementing calculation between two fields, and the result within another field. Suppose I have three fields called A B and C respectively. In the form I plan on Inputing a value for[A] and Inputing a value for [B]. Now, Field [C] will calculate [A]-[B]. When filed [C] is calculated, it is not in the table, like A and B are. I would like to know how to solve this problem. > >--- >frmsrcurl: http://msgroups.net/microsoft.public.access/ -- Message posted via AccessMonster.com http://www.accessmonster.com/Uwe/Forums.aspx/access/201003/1
From: ghetto_banjo on 26 Mar 2010 14:39 You may find it best not to store Field C in the table at all. Storing fields that are calculated from other fields can be a little dangerous for data integrity. If someone updates Field A or B, Field C could then be storing the incorrect value. Instead, just calculate C whenever you need it via a query/report.
From: Daryl S on 26 Mar 2010 14:46
Graeme - First, is control [C] bound to a field in the table? Second, when are you calculating [C]? It should be before the record is saved (e.g. in the BeforeUpdate event on the form (not on the BeforeUpdate of a field). -- Daryl S "Graeme" wrote: > Hello > I palnning on implementing calculation between two fields, and the result within another field. Suppose I have three fields called A B and C respectively. In the form I plan on Inputing a value for[A] and Inputing a value for [B]. Now, Field [C] will calculate [A]-[B]. When filed [C] is calculated, it is not in the table, like A and B are. I would like to know how to solve this problem. > > --- > frmsrcurl: http://msgroups.net/microsoft.public.access/ > . > |