[WB24]HReadSeekFirst on unknown value

Good day

Can someone please assist on what index to create and/or what search to use to find this record:

I have a table with vehicle registration numbers and start and end odo readings.

I want to find the last reading for a specific vehicle so I created an index on vehicle registration number and odo reading descending.

How to find the record if you don't have the last odo reading? I would have preferred not to use HExecuteSQLQuery as I think it might take to long.

Thanks in advance


Ericus Steyn

this should work:

//This first line will never find a value
hreadseek(MyFile,MyCompositeKey,[VehiculeRegistration,MAXTECHNICALLYPOSSIBLEODOREADING])
//but it will position the pointer in the file just AFTER your last record (the one you are looking for), so
hreadprevious(MyFile,MyCompositeKey)//SHOULD read your record, if it exists

//Finally, a test on VehiculeRegistration will verify that you are indeed on your desired record

Thanks for the reply Argus but it does not seem to work on my side.

I changed it to a query and it is actually very fast so I'm happy.

Regards