Stages of transaction isolation supported by Oracle

Question

Describe the main three stages of transaction isolation supported by Oracle?

Answer 1

Oracle supports read Serialize, committed and read-only transaction isolation stages. Since of the method Oracle System Change Number (SCN) values are processed, Oracle never reads unclean data. Serializable isolation is possible, however the application program must be written to process the ‘Cannot serialize’ exception. Applications can place locks clearly employing the SELECT FOR UPDATE commands however this is not recommended.