Posted by Steve Auerbach on October 22, 2005 at 08:07:32:
In Reply to: Multi-Keyed File, continued...> posted by Tom Fulton on October 20, 2005 at 11:28:32:
Tom's question is an excellent one. Maybe there is no such thing as a next record when using a secondary index. What does Excel do when you sort by a column. Do you get the same order everytime? I don't know.
Let's go one better. Why do we need a primary key at all. ACCESS and, I think dBase, allow a record number as the unique identifier. In our environment that would suggest secondary indices for a "sequential" file. And why not?
If there is no user data as the primary key then EVERY field in a record is maintainable. The user could change the customer number!
Or there is no such thing as a customer number. Think QuickBooks or Quicken.