Explanation:
To update information you need to use UPDATE command.
Incorrect Answers:
1: Since you don’t have to add any records to the table you don’t need the MERGE command.
2: Since you don’t have to add any records to the table you don’t need the MERGE command.
4: There is no ADD command in Oracle.
5: There is no ENTER command in Oracle.
6: You can enter the phone numbers for the existing employee records by using UPDATE command.
OCP Introduction to Oracle 9i: SQL Exam Guide, Jason Couchman, p. 267-270
Chapter 3: Manipulating Oracle Data

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