b_book1.gif (162 bytes)Data - Structures (Tree)

Tree application areas

Flight reservations

Indexes in databases

 A B+ Tree is commonly used to maintain database indexes, to enable the database records to be accessed in an order that is different to that in which the records are arranged.

Two common DBMS access methods use the B+ tree structure

  • ISAM - Index sequential access method. Limited to a single disk drive. May need to be rebuilt if structure becomes inefficient.
  • VSAM - Virtual sequential access method. May span several disk drives. Dynamically reorganises itself to maintain efficiency. Supported by many operating systems.

[Rev 12/03/99] 28/5/97 © 1997-99 V/2-Com (Verhaart), P O Box 8415, Havelock North, New Zealand.