kamlesh mishra

• May 18th, 2015

 

Default type of index is B-Tree - usually created when the column have more distinct or unique values like emp_no.
When column have sequential values e.g 111,112,113,114 then use reverse key index
when you have used any functions within where clause, then use functional index
When a column having low distinct values or cardinality values like gender column, which can be male and female, or course column for student which could be matric, isc,graduation, pg etc. you should go for bitmap index.

Code
CREATE <index_type> <index_name>  ON  <table_name> (column_name)