Indexes are crucial database objects of your database. Indexes help queries in fetching data using fewer system resources thereby speeding the queries. However, care should be taken when creating new indexes. Too many indexes will lead to negative database performance for DML statements and too few indexes would increase the response time of the queries. Read the How much expensive are indexes? post on my blog to understand the impact of having too many indexes for a table.
There are different types of indexes that you may find in Oracle. Below are a few of the index types.
B*Tree indexes: These are the most commonly used indexes in the Oracle database. They are named after a computer science construct of the same name. B*Tree indexes provide a faster access to an individual row or range of rows normally requiring few system resources. In a B*Tree, every new table record with a not null indexed column will have an entry in the index. The indexes created earlier in this book...
