loop through records and add record or create if none exists to new table depending on multiple criteria - sql

Question

I'm new to access/vba and trying to set up a project database. I have a table ("Updates") that is generated when changes are made to certain fields on a form (used for project updates by the end user). It has the primary key UpdateID, foreign key ProjectID as well as UTimeStamp, OldValue, NewValue, History. I use the history key to identify which type of update was made (for example for Status, History=1). I want to then count the number of projects for each status at the end of each month, keeping historical data to allow users to track the changes from month to month (or even compare data from months apart). I'm trying to write a code (in VBA for access) that would take into account that there are sometimes multiple status updates in each month and I don't want them to get counted twice, also some months no updates are made but I still want them included in the count (using the last updated status before that month as the status).
I was thinking of using a combination of looping through the records and checking to see if a value exists for that specific ProjectID and month and inserting the last value (most recent) into a new table "StatusTracking" and if no record exists then using the INSERT INTO function to add a new record. "StatusTracking" will have the fields ID, ValueMonth, ValueYear, (since ideally I want to track over the course of more than a year) Status, ProjectID. However, I am very new to this and am having trouble getting started as I'm not sure the best way to loop through both the months and ProjectID.
Public Function getStatus()
Dim varMonth As Integer
Dim ReportStatus As String
Dim RS As DAO.Recordset
Dim db As DAO.Database
Dim sqlStr As String
sqlStr = "SELECT Updates.ProjectID, Format(Month([UTimeStamp])) AS UpdateMonth, ProjectList.Status, Updates.NewValue, Updates.UTimeStamp" & _
"FROM Updates RIGHT JOIN ProjectList ON Updates.ProjectID = ProjectList.ProjectID" & _
"WHERE (((Updates.History) = 1))" & _
"GROUP BY Updates.ProjectID, Format(Month([UTimeStamp])), ProjectList.Status, Updates.NewValue, Updates.UTimeStamp"
Set db = CurrentDb
Set RS = db.OpenRecordset(sqlStr)
With RS
.MoveLast
.MoveFirst
While (Not .EOF)
'Cycle through each month
For varMonth = 1 To 12 Step 1
ReportStatus = DLast("NewValue", RS, "UpdateMonth = " & varMonth)
RS.Fields ("Status") <> RS.Fields("NewValue")
End Function
Any help is appreciated!

Answer 1

DCount is useful for counting unique occurrences in a specified field. The link I provided should put you on the right track there. Note that that only returns the count itself, and not the records. If you need to populate a recordset, you can use SELECT DISTINCT in your query to return only the records that have, well, distinct values in your criteria.
I recently worked on a project that involved building a history table for tracking purposes. Since it was based around forms, I opted for using .addnew and .update rather than INSERT INTO. Of course, use what's best for the situation at hand; I used .addnew and .update for the main reason that I had a lot of controls in my form and it was simpler in my mind to do it that way. There's lots of ways to do it, this worked best for me. I've also provided a snippet of the code I wrote for that project as another example.
Hope this helps!
'Example
'Assuming recordset and database variables are already declared
'rec = recordset, db = currentdb
set rec = db.openrecordset(<source table, name of existing query, or SQL query>)
if <condition is met> then
'populate table with values in form controls
rec.addnew
rec("Destination Table Field") = Me.Controls("Name of Form Control").Value
.
.
.
rec.update
set rec = nothing
set db = nothing
'clearing rec and db after done using
end if
Code from my project:
Set db = CurrentDb
Set rec = db.OpenRecordset("Select * from tbl_maintenanceOrders")
Set recHist = db.OpenRecordset("Select * from tbl_umoHistory")
msgConfirm = MsgBox("Correct values confirmed?", vbYesNo, "Continue")
'enter record in maintenance order table
If msgConfirm = vbYes Then
rec.AddNew
recHist.AddNew
rec("openTimestamp") = Now()
rec("openedBy") = Me.Controls("cbo_originator").Value
rec("assetID") = Me.Controls("cbo_asset").Value
rec("assetDesc") = Me.Controls("txt_assetDesc").Value
rec("priority") = Me.Controls("cbo_priority").Value
rec("umoProblemDesc") = Me.Controls("txt_issueDesc").Value
rec("umoSpecifics") = Me.Controls("txt_issueDetails").Value
rec("umoState") = "open"
rec("umoStatus") = "new"
rec.Update
'add UMO history entry
recHist("umoID") = rec("orderID")
recHist("activity") = "opened"
recHist("umoState") = "open"
recHist("umoStatus") = "new"
recHist("activityDesc") = "UMO Requested"
recHist("initiatorID") = Me.Controls("cbo_originator").Value
recHist("timeStamp") = Now()
recHist("updater") = Me.Controls("cbo_originator").Value
recHist.Update
End If
'cleanup
Set rec = Nothing
Set recHist = Nothing
Set db = Nothing