View the Exhibit and examine the structure of the SALES, CUSTOMERS, PRODUCTS, and TIMES tables.
The PROD_ID column is the foreign key in the SALES table, which references the PRODUCTS table.
Similarly, the CUST_ID and TIME_ID columns are also foreign keys in the SALES table referencing the CUSTOMERS and TIMES tables, respectively.

Evaluate the following CREATE TABLE command:
CREATE TABLE new_sales(prod_id, cust_id, order_date DEFAULT SYSDATE)
AS
SELECT prod_id, cust_id, time_id
FROM sales;
Which statement is true regarding the above command?
A. The NEW_SALES table would not get created because the DEFAULT value cannot be specified in the column definition.

B. The NEW_SALES table would get created and all the NOT NULL constraints defined on the specified columns would be passed to the new table.
C. The NEW_SALES table would not get created because the column names in the CREATE TABLE command and the SELECT clause do not match.D. The NEW_SALES table would get created and all the FOREIGN KEY constraints defined on the specified columns would be passed to the new table

看下圖中SALES, CUSTOMERS, PRODUCTS, and TIMES這幾張表的結構，SALES表有一個外來鍵列PROD_ID,關聯到PRODUCTS表。類似地，CUST_ID and TIME_ID 列也是SALES表的外來鍵列，分別關聯到表CUSTOMERS和表TIMES,
下面的這條CREATE TABLE建表命令：
CREATE TABLE new_sales(prod_id, cust_id, order_date DEFAULT SYSDATE)
AS
SELECT prod_id, cust_id, time_id
FROM sales;
關於這個命令，下面哪一種說法是正確的：
A.NEW_SALES這張表不能建立成功，因為列定義時，不能指定預設值。
B.NEW_SALES這張表能建立成功，並且所有 指定列上的已定義的非空約束會帶到新表。
C.NEW_SALES表不能建立成功，因為CREATE TABLE命令中的列名與SELECT子句中的列名不匹配。
D.NEW_SALES表可以建立成功，並且所有指定列上的已定義的外來鍵約束會帶新表。

        使用CREATE TABLE..AS..語句建立表時，原表列上如果有顯式非空約束會傳遞給新表，其它約束都不會帶到新表。