How increment number by 1 when text field is one of three choices

SteveL13
SteveL13 used Ask the Experts™
on
I have a form which has a field which has been populated from an option group on a separate form for the creation of a new record.  This text field, named "txtDrawingType", has either been populated with a "M", a "P", or a "I" from the option group in the separate form.

On this same form is a field named "txtDrawingNumber".  This field can hold a value between:

If "M" in field "txtDrawingType" -  1,000 to 29,999
If "P" in field "txtDrawingType" -  30,000 to 39,999
If "I" in field "txtDrawingType" -  40,000 to infinity

Here is the challenge.  For example, if the drawing type is "M", and the last record written for a "M" type drawing is 1,205 (for example), then the new "txtDrawingNumber" needs to be 1,206.

As another example, using a drawing type of "I", if the last record written had a drawing number of 50,234 then the new record needs to have its drawing number be 50,235.

I have no idea where to begin.  Can someone help?

Thanks,

Steve
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Commented:
This is typically a bad practice.  to lock in ID's in such a way.  I presume this is all stored to a database.  It would be better to have an extra field which stores [Type] {"M", "P" or "I"} and let the ID auto increment.  This design only works if you purposefully hope that your users will never store more than 29k M's, or 10k P's.

Commented:
Are The numbers and drawing types in the same table?
Jeffrey CoachmanMIS Liason
Most Valuable Expert 2012

Commented:
I'm with hpdvs2.
Because if we did devise this system for you , we would also need to know what happens when the "P" value is 39,999...? ( and when M reaches 29999)

So can you take a step back and explain the meaning behind the M, P and I designations?
...perhaps there is an alternate method.
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Author

Commented:
To all so far... I totally agree with you that this is a bad way to do this.   But this is what the end user wants and say the numbering scheme will NEVER go beyond the given ranges.  So, that being what it is, I have to do it this way.  And yes, the numbers and drawing types are in the same table.

Commented:
on some event
me.FieldtoHoldValue = dmax("fieldWithIMP", "tableWithIMP", "fieldWithIMP= '" & me.txtDrawingType & "'") +1

Commented:
Rather
me.FieldtoHoldValue = dmax("fieldWithNumber", "tableWithIMP", "fieldWithIMP= '" & me.txtDrawingType & "'") +1
Jeffrey CoachmanMIS Liason
Most Valuable Expert 2012

Commented:
OK but you still have not told us what should happen when a the M and P limits are reached...

Author

Commented:
I'm getting a "You can't assign a value to this object ... on....

Me.txtDrawingNumber = DMax("DrawingNumber", "tblDrawings", "DrawingType= '" & Me.txtDrawingType & "'") + 1

Commented:
Is this an unbound textbox?
If you type in the debug window
?  DMax("DrawingNumber", "tblDrawings", "DrawingType= '" & Me.txtDrawingType & "'") + 1
do you get a value?
Jeffrey CoachmanMIS Liason
Most Valuable Expert 2012

Commented:
Check the ControlSource properties of that control...

It should look like this:
ControlSource: DrawingNumber

*not* like this:
ControlSource: =DrawingNumber

Jeff

Author

Commented:
It is DrawingNumber not =DrawingNumber

But, and this may be a clue... for whatever reason, the DrawingNumber field is a text field.

Commented:
Can you post a small db with some dummy data?

Author

Commented:
To Jerryb30...

Is this an unbound textbox?  - No
If you type in the debug window
?  DMax("DrawingNumber", "tblDrawings", "DrawingType= '" & Me.txtDrawingType & "'") + 1
do you get a value?  Yes.  And it IS the next incremental number I would expect.
Jeffrey CoachmanMIS Liason
Most Valuable Expert 2012

Commented:
Jerry,

I'll leave this in your capable hands

;-)

Jeff
Commented:
Create an unbound textbox to hold the value, and when you save your record, use that to populate the bound control.

Commented:
Jeff, your input is always welcome.
Jeffrey CoachmanMIS Liason
Most Valuable Expert 2012

Commented:
I'll still monitor.
I just want to step aside to avoid confusion with too many experts posting...

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