Re: forumla for index w.r.t cardinality

Sigh, its been a while, but you could look at log(x) or ln(x) to determine the number of levels in an index search? (Where x = number of rows in the table). Of course you have to consider which row(s) to include in the index... A good rule of thumb... 1000 rows or less, some databases will ignore the index and do a sequential search of the tables. But hey, what do I know? rkusenet wrote: > For a data mart table, is there a thumb-rule for > number of rows/cardinality to decide whether it is > worth indexing a column or not. Basically I plan > to write a script which will count the number of > rows and take the cardinality and using some > thumb rule will 'advise' me to create an index. > > TIA. > >