wallis@labc.dec.com (Barry L. Wallis) (03/18/90)
In article <33095@shemp.CS.UCLA.EDU>, ravi@maui.cs.ucla.edu (T.M Ravi) writes... > >I remember seeing a bunch of messages a few months back about B/B+ trees. >We already have the design of locking and transaction and buffer management >worked out and are trying to design a traditional high performance index >manager using B+ trees. > This brings up a question that I've wondered about from time to time (bit never for very long ;-) ). What is the difference between a B tree and a B+ tree? --- Barry L. Wallis USENET: wallis@labc.dec.com Database Consultant Prodigy (don't laugh): DNMX41A U.S. DECtp Resource Center DECUServe: EISNER::WALLIS (not on the net yet) Los Angeles, CA "No one voted for me, I represent myself" ---
staceyc@sco.COM (Stacey Campbell) (03/20/90)
In article <1467@mountn.dec.com> wallis@labc.dec.com (Barry L. Wallis) writes: >What is the difference between a B tree and a B+ tree? "The index set is actually a tree structure index to the sequence set; in fact, it is the index set that is the real B tree, strictly speaking. (The combination of index set and sequence set is sometimes called a B+ tree.)" C.J. Date, An Introduction to Database Systems, 3rd edn, pg 47. (4 edn, pg 64) -- Stacey Campbell _--_|\ {uunet,ucscc,decwrl,att,microsoft,wyse}!sco!staceyc / \ staceyc@sco.com \_.--._/ v
tony@cairo.UUCP (Tony Anzelmo) (03/20/90)
In article <1467@mountn.dec.com> wallis@labc.dec.com (Barry L. Wallis) writes: > >In article <33095@shemp.CS.UCLA.EDU>, ravi@maui.cs.ucla.edu (T.M Ravi) writes... >> >>I remember seeing a bunch of messages a few months back about B/B+ trees. >>We already have the design of locking and transaction and buffer management >>worked out and are trying to design a traditional high performance index >>manager using B+ trees. >> > >This brings up a question that I've wondered about from time to time (bit never >for very long ;-) ). What is the difference between a B tree and a B+ tree? > In a B+ tree, all data is moved to the leaf nodes. The upper level nodes only provide the search path. In addition, leaf nodes are linked together into a "sequence set" that allows simple sequential access in addition to efficient random access normally associated with B trees. The best paper on B trees I've seen is "The Ubiquitous B-Tree" by Douglas Comer. Computing Surveys, Vol. 11, No. 2, June 1979. Tony Anzelmo Anzelmo Assoc. Inc. 508-568-1880 ...!linus!alliant!cairo!tony