Which of the following options are best practices when creating database indexes?

When you use SQL statements to access tables in a database without an index configured, a full table scan will be performed. If a table contains a large amount of data, this kind of scan will access a large amount of data and consume a lot of the database’s resources.

Which of the following options are best practices when creating database indexes? (Number of correct answers: 3)
A . Add an index to a field that is frequently queried but does not frequently perform add, delete, or modify operations.
B . Applies indices to fields to contain many records.
C . A table should not contaiiAiore than 6 indexed fields.
D . Apply indexing to fields of fixed length (preferably not long fields).
E . Adhere to the rightmost prefix principle when using composite indexes

Answer: A,C,D