Re: strategy for data entry in multiple tables

OK...big list...ditch listboxes and use combo boxes instead. A single form
for the junction data. Bird and Event are combo and you say the bird has a
number. Whenever the data entry person enters a bird number in the junction
data form that is not in the combo list, the not in list event fires and
asks the user if they want to enter a new bird...it then opens up the form
for entering the bird, with the number already entered...then the user just
needs to make whatever other entries are appropriate for Bird, saves the
record and closes the form. If you use the not in list event correctly, the
bird will now be in the list and the user can continue on with the other
junction data entries. Do the same for other fields like event and any
others that are.

Here is an example of the code you'd need for the not in list event:

'This code goes in the Not In List event for the Bird combo in the junction
data entry form
Private Sub cboBird_NotInList(NewData As String, Response As Integer)

Dim i As Integer
Dim Msg As String

Msg = NewData & " is not currently in the list." _
& vbCr & vbCr & "Do you want to add a new bird?"

i = MsgBox(Msg, vbQuestion + vbYesNo, "Bird not found")
If i = vbYes Then
Response = acDataErrAdded

'Open form to enter bird
DoCmd.OpenForm "frmBird", , , , acFormAdd, acDialog, NewData

'See if user added the bird...if they did, the new number will
be in the table
If IsNull(DLookup("BirdNum", "tblBird", "BirdNum=" & NewData)) =
False Then
Response = DATA_ERRADDED
Else
Response = DATA_ERRCONTINUE
End If

Else
Response = acDataErrContinue
Exit Sub
End If
End Sub


'This code goes in the entry form for Bird
Private Sub Form_Load()

If IsNull(Me.OpenArgs) = False Then
Me.txtBirdNum = Me.OpenArgs
End If

End Sub





--
Paul Overway
Logico Solutions
http://www.logico-solutions.com


"LAF" <LAF@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:08598629-0C89-49E3-AED1-D59EB2657EB3@xxxxxxxxxxxxxxxx
> Thanks, Paul,
>
> The problem I see with list boxes is that the database has about 9000
> birds
> and about 7800 events. Plus, for data verification purposes, the user
> should
> not need to know if the entry is "not in list". Maybe the thing to do is
> to
> keep the 2nd and 3rd forms hidden and become unhidden as necessary.
>
> For example, on the first form, the user would enter bird number (from its
> band) and capture.type (whether it is an initial capture or a recapture).
> The data validation would be to send the user to an error table with its
> own
> data entry form if capture is initial and the bird number already exists,
> or
> if capture is recapture and the bird number does not exist. These are
> errors. Assuming that there is no error, the next step is to determine if
> a
> new eventID is necessary or to bring up an existing one. While an
> existing
> event is probably from a recent record, I prefer to validate the data by
> testing whether a similar event exists or not.
>
> The majority of the data entry will be in the junction table and in
> smaller
> tables that have one to one relationship with it. Am I understanding your
> previous message?
>
> All the best,
>
> LAF
>
>
> "Paul Overway" wrote:
>
>> Yes...the simpler way is what I described previously...although if you
>> want
>> a clear method for users to add to the listboxes I described, you'd need
>> to
>> include a "New" button for Birds and one for Events. An alternative is
>> to
>> display only the junction data and use the not in list event to add new
>> records for either Birds or Events as needed....the not in list event
>> would
>> cause the appropriate form to be displayed for the user to enter the Bird
>> or
>> the Event if it isn't in the list.
>>
>> I think what you are really missing here is the utility of the Not In
>> List
>> event in this situation...I'm sure you can do some reading on that.
>>
>> I'd stay away from having 3 forms up at the same time...too distracting
>> for
>> users. While you do need data entry forms for Birds and Events, they
>> should
>> be brought up as dialogs just when the user needs to add a new record vs
>> always there cluttering up the screen.
>>
>>
>> --
>> Paul Overway
>> Logico Solutions
>> http://www.logico-solutions.com
>>
>>
>> "LAF" <LAF@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
>> news:961947EB-6F4E-4471-87D1-72E0C6688184@xxxxxxxxxxxxxxxx
>> > Thanks Paul and Bruce,
>> >
>> > This is what makes the community group so valuable.
>> >
>> > The issue of data entry for master tables and junction tables, with
>> > referential integrity and cascading update, has to be one of the most
>> > general
>> > in Access. It is completely neglected in the 5 or so books I have on
>> > Access.
>> >
>> >
>> > The following subissues are involved in every single access data base
>> > with
>> > referential integrity.
>> >
>> > 1. Need to determine if a new record needs to be written in neither,
>> > one,
>> > or both master tables.
>> >
>> > 2. The master table primary key values, whether for newly written
>> > record
>> > or
>> > previous record, need to be entered into appropriate fields of the
>> > junction
>> > table data entry form.
>> >
>> > I am currently experimenting with a 3-form model, one form for each
>> > master
>> > table and one for the junction table. All 3 will be on screen. The
>> > user
>> > will first use one of the master table forms to determine if a new
>> > record
>> > needs to be written. If so, the data entered on this form will be used
>> > to
>> > create the new record, and the primary key value will be copied to the
>> > foreign key field on the junction data entry form. If a new record
>> > does
>> > not
>> > need to be written, the primary key value that was inputted will copied
>> > to
>> > the foreign key field (through code).
>> >
>> > This procedure will occur for each master table in sequence. The user
>> > will
>> > simply be left with the larger junction table data entry form with the
>> > foreign keys filled in from the previous master table forms. Subforms
>> > can
>> > then be used for data tables that are in one to one correspondence with
>> > the
>> > junction table.
>> >
>> > This is a little involved, but the code that underlies this serves for
>> > data
>> > validation as well as entry. My question thus becomes: is there a
>> > simpler
>> > way to get the foreign key values on the junction table data entry
>> > form?
>> >
>> > All the best,
>> > LAF
>> >
>> >
>> > "Paul Overway" wrote:
>> >
>> >> It makes sense because birds are being captured collectively as a
>> >> group
>> >> in
>> >> nets. If they were being captured individually, the junction would be
>> >> unnecessary....a bird would be related to events in a one to many.
>> >> But
>> >> because the birds are captured collectively, the junction is used to
>> >> resolve
>> >> what birds were captured during an event and vice versa.
>> >>
>> >> --
>> >> Paul Overway
>> >> Logico Solutions
>> >> http://www.logico-solutions.com
>> >>
>> >>
>> >> "BruceM" <BruceM@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
>> >> news:1F96B97E-6A9E-4A84-B911-C527B1EBD230@xxxxxxxxxxxxxxxx
>> >> > Interesting discussion, but it leaves me wondering how tblEvents and
>> >> > tblBirds
>> >> > are related many-to-many unless an individual bird could be captured
>> >> > several
>> >> > times. I see how each event could involve many birds, but not the
>> >> > other
>> >> > way
>> >> > around. What relationship is the junction table resolving? I would
>> >> > have
>> >> > imagined based on my understanding of the question that it would be
>> >> > Events
>> >> > >
>> >> > Birds > Bird Details in a cascading one-to-many relationship, with
>> >> > nested
>> >> > subforms. I don't really need an answer, but I am a bit curious as
>> >> > to
>> >> > how
>> >> > this discussion will unfold.
>> >> >
>> >> > "Paul Overway" wrote:
>> >> >
>> >> >> Ah...ok. I see what you're trying to do now.
>> >> >>
>> >> >> I'd have a single unbound entry form for this, with 2
>> >> >> listboxs...one
>> >> >> for
>> >> >> Birds, and another for Events. I'd have an Add button that would
>> >> >> add
>> >> >> a
>> >> >> record to a subform for the Junction data. I'd use the selections
>> >> >> from
>> >> >> the
>> >> >> 2 listboxes in the link master/link child property for the subform,
>> >> >> which
>> >> >> would allow you to see how the 2 master tables are related and the
>> >> >> junction
>> >> >> data for that combination.
>> >> >>
>> >> >> --
>> >> >> Paul Overway
>> >> >> Logico Solutions
>> >> >> http://www.logico-solutions.com
>> >> >>
>> >> >>
>> >> >> "LAF" <LAF@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
>> >> >> news:B666C61F-16CB-4053-A0F4-4D3A63A51E24@xxxxxxxxxxxxxxxx
>> >> >> > Hello All,
>> >> >> >
>> >> >> > Thanks for the stimulating discussion. Let me go back to the
>> >> >> > original
>> >> >> > problem. The data entry form is not to look at records, it is
>> >> >> > for
>> >> >> > entering
>> >> >> > (and validating) data. I don't see how a subform for the
>> >> >> > junction
>> >> >> > table
>> >> >> > can
>> >> >> > be used appropriately with a form for just one of the master
>> >> >> > tables.
>> >> >> > The
>> >> >> > foreign key for the other master table will be present, but the
>> >> >> > data
>> >> >> > entry
>> >> >> > needs to go into the primary key of the other master table.
>> >> >> >
>> >> >> > By the way, the database I am developing is for capturing birds
>> >> >> > in
>> >> >> > mist
>> >> >> > nets. We put numbered aluminum bands on the legs of birds we
>> >> >> > capture.
>> >> >> > tblBirds lists each individual by band number (=BirdID) as the
>> >> >> > primary
>> >> >> > key,
>> >> >> > with other fields such as species, leftleg, rightleg (for those
>> >> >> > birds
>> >> >> > on
>> >> >> > which we place color bands as well). tblEvents lists each
>> >> >> > capture
>> >> >> > event
>> >> >> > by
>> >> >> > site, date, and time. The EventID is an autonumbered field that
>> >> >> > is
>> >> >> > based
>> >> >> > on
>> >> >> > unique combinations of site, date, and time. The junction table
>> >> >> > deals
>> >> >> > with
>> >> >> > the many to many relationship between BirdID and EventID. The
>> >> >> > junction
>> >> >> > table
>> >> >> > has many fields that deal with data collected on birds captured
>> >> >> > in
>> >> >> > nets,
>> >> >> > and
>> >> >> > is in one to one relationship with tables with specialized data
>> >> >> > on
>> >> >> > particular
>> >> >> > birds. This is where I see a subform for data entry being
>> >> >> > useful.
>> >> >> >
>> >> >> > If both master tables could be used in the same data entry form,
>> >> >> > then
>> >> >> > subforms would be feasible for the junction table. Is it
>> >> >> > possible
>> >> >> > for
>> >> >> > two
>> >> >> > tables to be in the same form, each with their own primary keys,
>> >> >> > and
>> >> >> > then
>> >> >> > to
>> >> >> > use the junction table as a subform?
>> >> >> >
>> >> >> > Thanks,
>> >> >> >
>> >> >> > LAF
>> >> >> >
>> >> >> > "Paul Overway" wrote:
>> >> >> >
>> >> >> >> I think you're misusing or misinstanding keys. You should have
>> >> >> >> a
>> >> >> >> PK
>> >> >> >> in
>> >> >> >> Event, another PK in Subject, and 2 FK (EventID and SubjectID)
>> >> >> >> in
>> >> >> >> the
>> >> >> >> junction. You shouldn't be putting an FK in either of the
>> >> >> >> master
>> >> >> >> tables.
>> >> >> >> Example
>> >> >> >>
>> >> >> >> Event
>> >> >> >> 1 Gala
>> >> >> >> 2 Dinner
>> >> >> >>
>> >> >> >> Subject
>> >> >> >> 1 Funding
>> >> >> >> 2 Purpose
>> >> >> >>
>> >> >> >> Junction
>> >> >> >> Event Subject
>> >> >> >> 1 1
>> >> >> >> 1 2
>> >> >> >> 2 2
>> >> >> >>
>> >> >> >> In the example above, I've omitted one of the possible
>> >> >> >> combinations.
>> >> >> >> Nevertheless, we can see for the Gala the subject will be
>> >> >> >> Funding
>> >> >> >> and
>> >> >> >> Purpose, whereas for the Dinner the only subject will be
>> >> >> >> purpose.
>> >> >> >> If
>> >> >> >> you
>> >> >> >> have a subform for Junction on the Event form and on the Subject
>> >> >> >> form,
>> >> >> >> you
>> >> >> >> can see what subjects will be discussed at the event or at what
>> >> >> >> event
>> >> >> >> the
>> >> >> >> subject will be discussed.
>> >> >> >>
>> >> >> >> --
>> >> >> >> Paul Overway
>> >> >> >> Logico Solutions
>> >> >> >> http://www.logico-solutions.com
>> >> >> >>
>> >> >> >>
>> >> >> >> "LAF" <LAF@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
>> >> >> >> news:E136D420-8C1D-4B6E-AEC4-68EA6E0C1D97@xxxxxxxxxxxxxxxx
>> >> >> >> > Hi Paul,
>> >> >> >> >
>> >> >> >> > Thanks for the advice. Let us assume that there is one to
>> >> >> >> > many
>> >> >> >> > relationship
>> >> >> >> > between a master table and the junction table, for each master
>> >> >> >> > table.
>> >> >> >> > There
>> >> >> >> > is not necessarily one to one between the two master tables.
>> >> >> >> >
>> >> >> >> > In principle then, it appears that the best strategy is to
>> >> >> >> > combine
>> >> >> >> > data
>> >> >> >> > entry and validation for each master table separately, and
>> >> >> >> > then
>> >> >> >> > to
>> >> >> >> > copy
>> >> >> >> > the
>> >> >> >> > primary field to the data entry form for the junction table.
>> >> >> >> > I
>> >> >> >> > assume
>> >> >> >> > that
>> >> >> >> > there would be no problem with referential integrity to have a
>> >> >> >> > new
>> >> >> >> > record
>> >> >> >> > in
>> >> >> >> > a master field with no foreign key, yet, put in a new record
>> >> >> >> > in
>> >> >> >> > the
>> >> >> >> > junction
>> >> >> >> > table. Is this correct?
>> >> >> >> >
>> >> >> >> > Thanks,
>> >> >> >> >
>> >> >> >> > LAF
>> >> >> >> >
>> >> >> >> > "Paul Overway" wrote:
>> >> >> >> >
>> >> >> >> >> Comments in-line
>> >> >> >> >>
>> >> >> >> >> "LAF" <LAF@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
>> >> >> >> >> news:62C2C75F-0B93-47EE-8130-2728711D1134@xxxxxxxxxxxxxxxx
>> >> >> >> >> >A great strength of Access is the ability to base a form on
>> >> >> >> >> >a
>> >> >> >> >> >multi-table
>> >> >> >> >> > query and use the form for data entry. However, there are
>> >> >> >> >> > some
>> >> >> >> >> > important
>> >> >> >> >> > issues. Let us assume a simple database with two master
>> >> >> >> >> > tables
>> >> >> >> >> > and
>> >> >> >> >> > a
>> >> >> >> >> > junction table. One master table (subjects) has a primary
>> >> >> >> >> > key
>> >> >> >> >> > that
>> >> >> >> >> > is
>> >> >> >> >> > a
>> >> >> >> >> > text
>> >> >> >> >> > variable. The other master table is an event table with an
>> >> >> >> >> > autonumbered
>> >> >> >> >> > EventID as primary key. Assume for this example that
>> >> >> >> >> > tblEventID
>> >> >> >> >> > has
>> >> >> >> >> > fields
>> >> >> >> >> > EventID, Site, Date, Time.
>> >> >> >> >> >
>> >> >> >> >> > Issue 1. Should there be a single bound data entry form
>> >> >> >> >> > that
>> >> >> >> >> > has
>> >> >> >> >> > all
>> >> >> >> >> > fields
>> >> >> >> >> > from all 3 tables? For this to occur, code or macro must
>> >> >> >> >> > be
>> >> >> >> >> > written
>> >> >> >> >> > to
>> >> >> >> >> > run
>> >> >> >> >> > after the SubjectID is entered in the SubjectID field from
>> >> >> >> >> > tblSubjecst,
>> >> >> >> >> > to
>> >> >> >> >> > determine if a new record should be written in the subjects
>> >> >> >> >> > table.
>> >> >> >> >> > If
>> >> >> >> >> > a
>> >> >> >> >> > new
>> >> >> >> >> > record does not need to be made, then the SubjectsID field
>> >> >> >> >> > should
>> >> >> >> >> > be
>> >> >> >> >> > cleared,
>> >> >> >> >> > but the SubjectsID value placed in the SubjectsID field
>> >> >> >> >> > from
>> >> >> >> >> > tblJunction.
>> >> >> >> >>
>> >> >> >> >> Maybe? What is the relationship between Subject and Event?
>> >> >> >> >> If
>> >> >> >> >> 1
>> >> >> >> >> to
>> >> >> >> >> 1,
>> >> >> >> >> ok.
>> >> >> >> >> But otherwise, it seems to me subject and event should be
>> >> >> >> >> separate
>> >> >> >> >> forms
>> >> >> >> >> with data from the junction table in a subform (if it makes
>> >> >> >> >> sense
>> >> >> >> >> to
>> >> >> >> >> show
>> >> >> >> >> the related data in both places). You seem to be concerned
>> >> >> >> >> about
>> >> >> >> >> duplicate
>> >> >> >> >> data in subject. Ok, so, do some validation before
>> >> >> >> >> update/insert
>> >> >> >> >> for
>> >> >> >> >> subject records....and if there is a duplicate, cancel the
>> >> >> >> >> update
>> >> >> >> >> and
>> >> >> >> >> go
>> >> >> >> >> to
>> >> >> >> >> the preexisting record or prompt the user to do so.
>> >> >> >> >>
>> >> >> >> >> >
>> >> >> >> >> > Issue 2. A bigger problem occurs when data are entered for
>> >> >> >> >> > tblEvent
>> >> >> >> >> > on
>> >> >> >> >> > the
>> >> >> >> >> > single bound entry form. Code or macro must be written to
>> >> >> >> >> > determine
>> >> >> >> >> > if
>> >> >> >> >> > the
>> >> >> >> >> > non-primary key fields are already present in tblEvents.
>> >> >> >> >> > If
>> >> >> >> >> > they
>> >> >> >> >> > are,
>> >> >> >> >> > then
>> >> >> >> >> > the EventID from the matching record should be copied into
>> >> >> >> >> > EventID
>> >> >> >> >> > field
>> >> >> >> >> > on
>> >> >> >> >> > the data entry form for tblEvents. If not, then a new
>> >> >> >> >> > record
>> >> >> >> >> > must
>> >> >> >> >> > be
>> >> >> >> >> > written
>> >> >> >> >> > into tblEvent and the autonumber copied into the data
>> >> >> >> >> > transfer
>> >> >> >> >> > form.
>> >> >> >> >> >
>> >> >> >> >>
>> >> >> >> >> This seems very similar to issue 1, and the solution is as
>> >> >> >> >> well.
>> >> >> >> >>
>> >> >> >> >> > The big question is: should there be separate data entry
>> >> >> >> >> > forms
>> >> >> >> >> > for
>> >> >> >> >> > the
>> >> >> >> >> > two
>> >> >> >> >> > master tables, possibly on unbound forms that pass
>> >> >> >> >> > appropriate
>> >> >> >> >> > values
>> >> >> >> >> > to
>> >> >> >> >> > the
>> >> >> >> >> > relevant data entry forms, or to an error event? The
>> >> >> >> >> > tblJunction
>> >> >> >> >> > data
>> >> >> >> >> > entry
>> >> >> >> >> > form would start out with the passed values in the foreign
>> >> >> >> >> > key
>> >> >> >> >> > fields.
>> >> >> >> >> > Is
>> >> >> >> >> > there a better strategy for dealing data entry with
>> >> >> >> >> > referential
>> >> >> >> >> > integrity
>> >> >> >> >> > and
>> >> >> >> >> > cascade updating.
>> >> >> >> >>
>> >> >> >> >> Yes 2 forms....with a subform for the junction data. Whether
>> >> >> >> >> bound
>> >> >> >> >> or
>> >> >> >> >> unbound, you're going to need to do validation to ensure that
>> >> >> >> >> any
>> >> >> >> >> new
>> >> >> >> >> record
>> >> >> >> >> is not a duplicate of an existing record. I'm not sure why
>> >> >> >> >> you'd
>> >> >> >> >> have
>> >> >> >> >> the
>> >> >> >> >> junction data on yet another form, if it is related to the
>> >> >> >> >> master
>> >> >> >> >> tables....just use a subform if possible....then the foreign
>> >> >> >> >> key
>> >> >> >> >> for
>> >> >> >> >> either
>> >> >> >> >> subject or event would be passed automatically.
>> >> >> >> >>
>> >> >> >> >> >
>> >> >> >> >> > LAF
>> >> >> >> >>
>> >> >> >> >>
>> >> >> >> >>
>> >> >> >>
>> >> >> >>
>> >> >> >>
>> >> >>
>> >> >>
>> >> >>
>> >>
>> >>
>> >>
>>
>>
>>


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