#Oracle #quiz

Examine the structure of CONTACT table.
CONTACT(CONTACT_ID NOT NULL NUMBER(3)
, NAME NOT NULL VARCHAR2(25)
, PHONE NOT NULL VARCHAR2(9)
, ADDRESS VARCHAR2(50))
There are hundred records in the contact table. You need to modify the Phone
column to hold only numeric value. Which statement will modify the data type of
the Phone column?

A. ALTER TABLE CONTACT MODIFY PHONE NUMBER(9)
B. ALTER CONTACT TABLE MODIFY COLUMN PHONE NUMBER(9);
C. You can not modify a VARCHAR2 data type to a NUMBER data type.
D. You cannot modify the data type of a column if there is data in the column.

Answer: [D]
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