Reviewing Table Creation Basics - Quiz Explanation

The correct answers are indicated below, along with text that explains the correct answers.

1.	Which one of these is syntactically correct? Please select the best answer.
	A.	`CREATE TABLE auction COLS(auction_id NUMBER, start_time DATE, stop_time DATE)`
	B.	`CREATE TABLE (auction_id NUMBER, start_time DATE, stop_time DATE)`
	C.	`CREATE TABLE auction (auction_id NUMBER, start_time DATE, stop_time DATE)`
	D.	`CREATE TABLE AUCTION (auction_id NUMBER, start_time DATE, stop_time)`
	C is correct. Answer A includes the superfluous word `COLS`. Answer B is missing a name for the table. Answer D is missing a datatype for the final column in the column list.

2.	You must define a column holding up to 800 English language characters. The best datatype for the column is: Please select the best answer.
	A.	`CHAR(800)`
	B.	`VARCHAR2(800)`
	C.	`CLOB`
	D.	`NVARCHAR2(800)`
	The correct answer is B. The best answer is B, since the `VARCHAR2` datatype will not waste space if the column is less than 800 characters, as the `CHAR(800)` datatype would. The `CLOB` will work, but since its extra space allowance is not needed, it is not the best datatype. The `NVARCHAR2` datatype can hold English characters, but there is no need to use it, since the `VARCHAR2` will also hold the characters.

3.	You want to store a string of 8,000 Japanese characters in a column. You would define the column with a datatype of: Please select the best answer.
	A.	`NCHAR(8000)`
	B.	`NVARCHAR2(8000)`
	C.	`NLOB`
	D.	`CLOB`
	The correct answer is C. For this task, you have to use a datatype that can accept `NLS` characters. Because you are storing more than 2,000 `NLS` characters, you cannot use `NCHAR` datatype. Because you are storing more than 4,000 Japanese characters, you cannot use `NVARCHAR2` datatype. And because you are storing Japanese characters, you cannot use the `CLOB` datatype. The `NLOB` datatype accepts up to 4 megabytes of `NLS` characters, and therefore the correct answer is C.