3. INDEX – consists of keys and addresses (physical disc locations.
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6. Adams, John Aaron, Ed Alexander, Ed Aaron, Ed Acosta, Marc Abbott, Diane (Primary key field) NAME DATA FILE SSN BLOCK ANCHOR PRIMARY KEY VALUE BLOCK POINTER BDATE JOB SALARY INDEX FILE (<K(i), P(i)>entries) Adams, John Adams, Robin Alexander, Ed Alfred, Bob Akers, John Allen, Sam PRIMARY INDEX
15. TYPES OF INDEXES ORDERING FIELD NON ORDERING FIELD Key field NonKey field Primary index Secondary index (nonkey) Secondary index (key) Clustering index
16. PROPERTIES OF INDEX TYPES No Dense or nondense Number of records or number of distinct index field values Secondary (nonkey) No Dense Number of records in data file Secondary (key) Yes/No Nondense Number of distinct index field values Clustering Yes Nondense Number of blocks in data file Primary BLOCK ANCHORING ON THE DATA FILE DENSE OR NONDENSE NUMBER OF (FIRST-LEVEL) INDEX ENTRIES TYPE OF INDEX
23. A K I H G D C J F E B Root node (level 0) nodes at level 1 Nodes at level 2 Nodes at level 3 SUBTREE FOR NODE B (nodes E, J, C, G, H, and K are leaf nodes of the tree) A tree data structure that shows an unbalanced tree.