Access VBA - How is this code grouping all info for one policy together? - ms-access

Question

So, I inherited some code (below) from someone else and I'm trying to understand how it works. I understand msot of the code (though I'm pretty new to Access VBA) but the one part I don't get is how this code groups all the info for one policy together.
The situation is as follows. To get premium data for a specific policy, from our company database, we have to get it one coverage per line. But, I want all premiums, one for each coverage, all on the same line. So, this code puts it all together from many lines into one line. For simplicity, I knocked it down to 3 total coverages, though there are many more. As I read the code, it seems to assume that all the info for one policy is together, like the 1, 2, or 3 rows for a specific policy are in order. But, even when I, for example, order the table by the premium (amount) column, it still gets all the premium for one policy on one line. I don't see anywhere in the code that should make this work. The code is comparing the policy number on one line to the policy number on the next. If they are the same, group the premium together. If they are different, don't. Again, I could order the table so that the records for one policy are not together, but the end result still comes out right. Am I missing something? Is it something in Access doing it? Thanks for any help!
Option Compare Database
Option Explicit
' Premium is imported with one row for each coverage per policy, so possibly several rows per policy.
' This procedure takes several rows per policy and makes them into one row.
Sub ScrubPremium()
Dim i As Long, j As Long, k As Long
Dim NumRecords As Long, found As Long, UniqueCount As Long
Dim tempPolicyNum As String, tempCoverage As String, tempPremium As Single
Dim PolicyNumArray() As String, PremiumArray() As Single, TotalPremiumArray() As Single
Dim db As DAO.Database
Set db = CurrentDb
Dim infile As Variant, outfile As Variant
Set infile = db.OpenRecordset("Imported Premium")
CurrentDb.Execute "DELETE * FROM [Finalized Premium]"
Set outfile = db.OpenRecordset("Finalized Premium")
NumRecords = infile.RecordCount
ReDim PolicyNumArray(NumRecords)
ReDim PremiumArray(NumRecords, 3)
ReDim TotalPremiumArray(NumRecords)
infile.MoveFirst
'initialize PremiumArray
For i = 1 To NumRecords
For j = 1 To NumPremiums
PremiumArray(i, j) = 0
Next j
Next i
'populate arrays
UniqueCount = 0
For i = 1 To NumRecords
tempPolicyNum = infile![Policy_Number]
tempCoverage = infile![Coverage]
tempPremium = infile![Premium]
k = 0
found = 0
Do Until k = UniqueCount Or found = 1 'check for unique policy
If tempPolicyNum = PolicyNumArray(k + 1) Then
found = 1
Else
k = k + 1
End If
Loop
If found = 0 Then
UniqueCount = UniqueCount + 1
PolicyNumArray(k + 1) = tempPolicyNum
End If
Select Case tempCoverage
Case "Comprehensive"
j = 1
Case "Collision"
j = 2
Case Else
j = 3
End Select
PremiumArray(k + 1, j) = PremiumArray(k + 1, j) + tempPremium
TotalPremiumArray(k + 1) = TotalPremiumArray(k + 1) + tempPremium
infile.MoveNext
Next i
'Populate table
For i = 1 To UniqueCount
outfile.AddNew
outfile![Full Policy Number] = PolicyNumArray(i)
outfile![Comp Premium] = PremiumArray(i, 1)
outfile![Coll Premium] = PremiumArray(i, 2)
outfile![Other Premium] = PremiumArray(i, 3)
outfile![Total Premium] = TotalPremiumArray(i)
outfile.Update
Next i
infile.Close
outfile.Close
End Sub

Answer 1

The code is comparing the policy number on one line to the policy
number on the next. If they are the same, group the premium together.
If they are different, don't.
Almost.
There are two loops here. One walks through each row of your input file. On each row of the input file, a second loop walks through (potentially all of) PolicyNumArray, looking for policy numbers that match the number taken from the input file.
If I were you, I'd step through this with the debugger. Make sure it's doing what you expect it to do. I'd want to look closely at this part (some lines snipped).
UniqueCount = 0
For i = 1 To NumRecords
k = 0
Do Until k = UniqueCount