In-depth understanding of Oracle indexes (6): a preliminary understanding of the application scenarios of the three major indexes in practice

(I) A table has many duplicate values in a column. The base is very small. What indexes should be created?

-- Create a bitmap index. For details, see the comparison of the lock costs between B-tree indexes and bitmap indexes.
For example:
Create bitmap index idx_bm_product on products (list_price) tablespace users;

(Ii) the value of a column in a table is increasing all the time. It is not a random number. What index should I create?

-- Reverse index, that is, reversed Index
For example:
Create index idx_rev on test (SAL) reverse;

For specific usage, see: in-depth understanding of Oracle indexes (5): definitions, disadvantages, and applicable scenarios of reverse indexes.

(3) A column in a table is placed in the function in normal SQL statements. What should I do to improve the search speed by using indexes?

-- Create a function index
For example:
Create index idx_fun on EMP (upper (name ));