>Hello Doug,
>
>>
>>....SQL uses btrieve but there's more overhead and speed isn't the primary issue anyway.
>
>SQL uses btrieve? I don't believe so...
>Perhaps you mean btree (as in binary tree indexes)?

B-tree is not binary tree, the "B" is for balanced. There are also B+trees and B*trees that are derived from B-trees.

Here is more detailed info: http://guides.oernii.sk/database_implementation/lecture12.html