Nov 1, 2018

Index of Oracle database

Typically developers index columns for three major reasons:

  1. To enforce unique values within a column
  2. To improve data access performance
  3. To prevent lock escalation when updating rows of tables that use declarative referential integrity
Oracle provides many indexing technologies including function based indexes which can index expressions, such as an upper function, text indexes which can index free form text, bitmapped indexes useful in data warehousing. You can also create indexed organized tables, you can use partition indexes and more. Sometimes it is best to have fewer indexes and take advantage of in memory capabilities.