sql - Does MS Access suppress primary key violations on Inserts?

Question

I am in the process of re-writing an MS Access database to SQL server and have found an strange issue in Access that I am hoping someone can help with.

I have a table let's call it 'Main' with a Primary Key on the Account that is indexed and doesn't allow for duplicates. Seems simple enough but my issue is occurring when data is getting Inserted.

My INSERT query is (the number of fields have been limited for brevity)

INSERT INTO Main (Account, SentDate, Amount)
SELECT C.Account, C.SentDate, C.Amount
FROM 
    (CALLS C LEFT JOIN Bals B ON C.Account = B.ACCT_ID) 
LEFT JOIN AggAnt A ON C.Account = A.Account

The issue is this, if I run the SELECT portion of my query I get 2365 records but when I run the INSERT I get 2364 records. So I did some checking and I found one Account is duplicated the difference between the records is the SentDate and the Amount. But Access is inserting only one of the records and not throwing any kind of error message or anything. There is nothing in the query that says select the most recent date, etc.

Sample Data:

Account    SentDate   Amount
12345678   8/1/2011   123.00
23456789   8/1/2011   45678.00
34567890   8/1/2011   7850.00
45678912   8/1/2011   635.00
45678912   5/1/2011   982.00
56789123   8/1/2011   2639.00

In the sample I have one account that is duplicated 45678912 when I run my INSERT, I get no errors and I get the record from 8/1/2011.

Why is Access not throwing an error when this violates the PK on the table? Is there some quirk in Access to select one record and just skip the other?

I am totally stumped by this issue so any help would be great.

Answer 1

How are you running the query? If you're using DoCmd.RunSQL, switch to using the .Execute method of a DAO database object, and use dbFailOnError.

Dim db As DAO.Database
Dim strInsert As String
strInsert = "your insert statement"
Set db = CurrentDb
db.Execute strInsert, dbFailOnError
Set db = Nothing

Edit: If Main is an ODBC link to a SQL Server table, I would examine the Errors Collection (DAO) after db.Execute strInsert, dbFailOnError