The BTREE file structure provides a rapid mechanism to support and quickly access sorted indices for database files. The BTREE system maintains a specific type of indexed key file and provides a number of powerful and easy to use features including:
Multiple keys may be maintained for a file.
Keys are defined as algebraic equations which may encompass multiple attributes as well as utilize the conversion processor.
Direct support for exploding keys (the equivalent of exploding sorts) provided, with each sort element optionally sorted as numeric and/or as descending values.
Direct support for keys on MultiValued fields provided, with control of attributes which are to be handled as MultiValued.
mvBASIC applications are interfaced to the BTREE system transparently.
Browse and lookup routines are supplied which allow forward/backward scrolling.
Application codes can be set up independent of the actual key structure.
Browse display columns are easily defined as algebraic equations.
Browse displays are defined independently for each key.
Effective multiuser locks ensure key file integrity.
Easy to use programs are provided for defining, creating, rebuilding, and deleting key files.
The following topics are presented in this section:
Using Lookup and Browse Routines
Source Code to Lookup Routines
Maintaining Key File Performance
Stack Code Calculator Function
Estimating a Key's Location and File Size
See Also
Guide to mvBase Files and Accounts Overview
Using the Terminal Control Language
Creating and Deleting Accounts