I have a one to many relationship between 2 files.
Although there are multiple matching records in the secondary file, the fields I am interested in are common.
THerefore i only want one of the secondary records to join to the primary record - avaioding duplicate logical records.
I know this could probably be achieved using an SQL query (perhaps a subselect to return unique records from the secondary file and join that record set to the primary) but performance needs to be fast so I don't think this would be appropriate.
I just want to get all the data in a logical format if possible rather than do more I/O in the code to look things up.