多项选择题
What are two reasons to create synonyms?（）
A. You have too many tables.
B. Your tables are too long.
C. Your tables have difficult names.
D. You want to work on your own tables.
E. You want to use another schema's tables.
F. You have too many columns in your tables.
相关考题
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多项选择题
Which three statements about subqueries are true?（）
A. A single row subquery can retrieve only one column and one row.
B. A single row subquery can retrieve only one row but many columns.
C. A multiple row subquery can retrieve multiple rows and multiple columns.
D. A multiple row subquery can be compared by using the “>” operator.
E. A single row subquery can use the IN operator.
F. A multiple row subquery can use the “=” operator. -
单项选择题
Which SQL statement returns a numeric value?（）
A. SELECT ADD_MONTHS(MAX(hire_Date), 6) FROM EMP;
B. SELECT ROUND(hire_date) FROM EMP;
C. SELECT sysdate-hire_date FROM EMP;
D. SELECT TO_NUMBER(hire_date + 7) FROM EMP; -
多项选择题
When should you create a role?（）
A. To simplify the process of creating new users using the CREATE USER xxx IDENTIFIED by yyy statement.
B. To grant a group of relate privileges to a user.
C. When the number of people using the database is very high.
D. To simplify the process of granting and revoking privileges.
E. To simplify profile maintenance for a user who is constantly traveling.
