File types(3)

• Indexed Sequential Access Method(ISAM)

• supports exact match, pattern match, range of values, part key specification
• But index are static, performance will reduce after file update

• B-tree:A tree structure,Appendix F(C).5.5

• supports exact match, pattern match, range of values, part key specification
• Dynamic index, but ISAM is more efficient if tables are not frequently updated.
• Each node in the tree is actually a disk page