多项选择题Which three are true? ()

A. A MERGE statement is used to merge the data of one table with data from another.
B. A MERGE statement replaces the data of one table with that of another.
C. A MERGE statement can be used to insert new rows into a table.
D. A MERGE statement can be used to update existing rows in a table.


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1.多项选择题Which two statements are true about constraints? ()

A. The UNIQUE constraint does not permit a null value for the column.
B. A UNIQUE index gets created for columns with PRIMARY KEY and UNIQUE constraints.
C. The PRIMARY KEY and FOREIGN KEY constraints create a UNIQUE index.
D. The NOT NULL constraint ensures that null values are not permitted for the column.

2.多项选择题Evaluate the SQL statement: TRUNCATE TABLE DEPT; Which three are true about the SQL statement? ()

A. It releases the storage space used by the table.
B. It does not release the storage space used by the table.
C. You can roll back the deletion of rows after the statement executes.
D. You can NOT roll back the deletion of rows after the statement executes.
E. An attempt to use DESCRIBE on the DEPT table after the TRUNCATE statement executes will display an error.
F. You must be the owner of the table or have DELETE ANY TABLE system privileges to truncate the DEPT table

3.单项选择题

You need to design a student registration database that contains several tables storing academic information.
The STUDENTS table stores information about a student. The STUDENT_GRADES table stores
information about the student's grades. Both of the tables have a column named STUDENT_ID. The STUDENT_ID column in the STUDENTS table is a primary key.
You need to create a foreign key on the STUDENT_ID column of the STUDENT_GRADES table that
points to the STUDENT_ID column of the STUDENTS table. Which statement creates the foreign key?()

A. CREATE TABLE student_grades (student_id NUMBER(12),semester_end DATE, gpa NUMBER(4,3), CONSTRAINT student_id_fk REFERENCES (student_id) FOREIGN KEY student (student_id));
B. CREATE TABLE student_grades(student_id NUMBER(12),semester_end DATE, gpa NUMBER(4,3), student_id_fk FOREIGN KEY (student_id) REFERENCES students (student_id));
C. CREATE TABLE student_grades(student_id NUMBER(12),semester_end DATE, gpa NUMBER(4,3), CONSTRAINT FOREIGN KEY (student_id) REFERENCES student (student_id));
D. CREATE TABLE student_grades(student_id NUMBER(12),semester_end DATE, gpa NUMBER(4,3), CONSTRAINT student_id_fk FOREIGN KEY (student_id) REFERENCES students (student_id));

4.多项选择题Which two statements about subqueries are true? ()

A. A subquery should retrieve only one row.
B. A subquery can retrieve zero or more rows.
C. A subquery can be used only in SQL query statements.
D. Subqueries CANNOT be nested by more than two levels.
E. A subquery CANNOT be used in an SQL query statement that uses group functions.
F. When a subquery is used with an inequality comparison operator in the outer SQL statement, the column list in the SELECT clause of the subquery should contain only one column.

5.单项选择题

Examine these statements:
CREATE ROLE registrar
GRANT UPDATE ON dtudent_grades TO registrar;
GRANT registrar to user1, user2, user3;
What does this set of SQL statements do? ()

A. The set of statements contains an error and does not work.
B. It creates a role called REGISTRAR, adds the MODIFY privilege on the STUDENT_GRADES object to the role, and gives the REGISTRAR role to three users.
C. It creates a role called REGISTRAR, adds the UPDATE privilege on the STUDENT_GRADES object to the role, and gives the REGISTRAR role to three users.
D. It creates a role called REGISTRAR, adds the UPDATE privilege on the STUDENT_GRADES object to the role, and creates three users with the role.
E. It creates a role called REGISTRAR, adds the UPDATE privilege on three users, and gives the REGISTRAR role to the STUDENT_GRADES object.
F. It creates a role called STUDENT_GRADES, adds the UPDATE privilege on three users, and gives the UPDATE role to the registrar.

6.单项选择题Which view should a user query to display the columns associated with the constraints on a table owned by the user? ()

A. USER_CONSTRAINTS
B. USER_OBJECTS
C. ALL_CONSTRAINTS
D. USER_CONS_COLUMNS
E. USER_COLUMNS

7.单项选择题The user Alice wants to grant all users query privileges on her DEPT table. Which SQL statement accomplishes this? ()

A. GRANT select ON dept TO ALL_ USER;
B. GRANT select ON dept TO ALL;
C. GRANT QUERY ON dept TO ALL_USERS
D. GRANT select ON dept TO PUBLIC;

8.单项选择题Which constraint can be defined only at the column level? ()

A. UNIQUE
B. NOT NULL
C. CHECK
D. PRIMARY KEY
E. FOREIGN KEY

9.多项选择题In which two cases would you use an outer join? ()

A. The tables being joined have NOT NULL columns.
B. The tables being joined have only matched data.
C. The columns being joined have NULL values.
D. The tables being joined have only unmatched data.
E. The tables being joined have both matched and unmatched data.
F. Only when the tables have a primary key/foreign key relationship.

10.单项选择题

The PRODUCTS table has these columns:
PRODUCT_ID NUMBER(4)
PRODUCT_NAME VARCHAR2(45)
PRICE NUMBER(8,2)
Evaluate this SQL statement:
SELECT *
FROM PRODUCTS
ORDER BY price, product _ name;
What is true about the SQL statement? ()

A. The results are not sorted.
B. The results are sorted numerically.
C. The results are sorted alphabetically.
D. The results are sorted numerically and then alphabetically.