Structure of the CUSTOMERS table

-Which of the following commands will increase the size of the CITY column in the CUSTOMERS table from 12 to 20 and increase size of the LASTNAME column from 10 to 14?
A) ALTER TABLE customers MODIFY (city VARCHAR2(+8),lastname VARCHAR2(+4));
B) ALTER TABLE customers MODIFY (city VARCHAR2(20),lastname VARCHAR2(14));
C) ALTER TABLE customers MODIFY (city (+8),lastname (+4));
D) ALTER TABLE customers MODIFY (city (20),lastname (14));

Question

Structure of the CUSTOMERS table
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-Which of the following commands will increase the size of the CITY column in the CUSTOMERS table from 12 to 20 and increase size of the LASTNAME column from 10 to 14?
A) ​ALTER TABLE customers MODIFY (city VARCHAR2(+8),lastname VARCHAR2(+4)); 
B) ​ALTER TABLE customers MODIFY (city VARCHAR2(20),lastname VARCHAR2(14)); 
C) ​ALTER TABLE customers MODIFY (city (+8),lastname (+4)); 
D) ​ALTER TABLE customers MODIFY (city (20),lastname (14));

Quizplus · Accepted Answer

The correct syntax for modifying the size of a column is to use the MODIFY clause, followed by the name of the column and the new data type and size. In this case, B is the correct choice as it correctly modifies the CITY column to be size 20 and the LASTNAME column to be size 14. The other choices contain incorrect syntax or incorrect data types and/or sizes.

Structure of the CUSTOMERS Table