[AccessD] Fastest Way

R,
I do similar things for income files (4 per week) and I simply use the
s/sheet input name.  Once it has been input, the filename is retained on a
field in the  table as the "source" and it is easy to check if that has
already been  processed.
If your files all have the same name,it  is easy  to append the year/month
to it.

Max


-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Rocky Smolin
Sent: 14 January 2010 15:01
To: 'Access Developers discussion and problem solving'
Subject: [AccessD] Fastest Way

Dear List:

I have a medical database into which lab tests are imported from a
spreadsheet (exported from a mainframe medical records database at a big
hospital).  Front and back ends are Access 2003. The table tblPatientTest
has (in addition to the autonumber PK) 5 fields:

Patient ID (FK)

Test ID (FK)

Test Date as Date/Time (indexed duplicates OK)

Test Time as long integer - value between 0000 and 2399 (indexed duplicates
OK)

Test Result - Text (indexed duplicates OK)

I'm using DAO to add the records to the table.  Imports will happen monthly
and the number of records will be on the order of 10,000-100,000 with mean
probably around 20k-40k.

As the tests are imported I want to check the table to see if the test
record is already present by finding a record which matches all 5 fields to
prevent duplicate test records from being entered.

Since the import will take place monthly, import time is not super critical
but before importing the user will run an Error Report which does all the
error checking that the import does without actually doing the import.  The
user then resolves the errors and when the Error report is clean, will run
the import.  So the error report may have to be run more than once to clean
the data.

It is possible that the user will try to import a spreadsheet that has
already been imported. So it's important to screen for duplicates. 

So I want to find the fastest method of checking for duplicate.

The obvious thing is rs.FindFirst on all five fields, but I'm thinking that
may take a really long time.

Another possibility would be to create a temporary table in the front end or
external mdb, and create indexed records by concatenating all five fields
and checking for dups on that table.  Probably faster than the first method
but creating the table could take a lot of time when the Patient Test table
has a few hundred thousand records in it.

Or I could add the field of concatenated fields to the table itself as the
records are added, indexed and maintain that.

Or some other method that I haven't thought of or don't know about.

Any advice welcome.

MTIA

 

Rocky Smolin

Beach Access Software

858-259-4334

www.e-z-mrp.com <http://www.e-z-mrp.com/> 

www.bchacc.com <http://www.bchacc.com/>