PPT Slide
Kolona koja se najvise koristi trebala bi da bude na pocetku indeksa. Zasto? Ako kreiramo indeks na osnovu tri kolone A, B i C, Oracle moze taj indeks koristiti ne samo za pretrazivanje po sve tri kolone, nego i za slucajeve kada su (A,B) i samo A poznato.
When appropriate, Oracle uses the entire index or a leading portion of the index. Assume an index named IDX1 is created on columns A, B, and C of table TAB1 (in the order A, B, C). Oracle uses the index for references to columns A, B, C (the entire index); A, B; or just column A. References to columns B and C do not use the IDX1 index. Of course, you can also create another index just for columns B and C.