数据库系统概念第6版第3章习题答案

答案仅供参考，有错误望在评论区提出

大学模式数据库的表格：

表格示例

习题

3.11

# a.
SELECT `name`
FROM student NATURAL JOIN takes NATURAL JOIN course
WHERE dept_name = 'Comp. Sci.'

# b.
SELECT `ID`, `name`
FROM student
EXCEPT
SELECT `ID`, `name`
FROM student NATURAL JOIN takes
WHERE `year` < 2009  

# c.
SELECT `dept_name`, MAX(salary)
FROM instructor
GROUP BY dept_name

#d.
SELECT MAX(salary)
FROM
(SELECT `dept_name`, MAX(salary)
FROM instructor
GROUP BY dept_name)

3.12

# a.
INSERT INTO course
VALUES('CS-001', 'Weekly Seminar', 'Comp. Sci.', 0)

# b.
INSERT INTO section(`year`, semester, sec_id)
VALUES('2009', 'Fall', 1)

# c.
INSERT INTO takes
SELECT ID, 'CS-001', 1, 'Fall', '2009', NULL
FROM student
WHERE dept_name = 'Comp. Sci.'

# d.
DELETE FROM takes
WHERE course_id = 'CS-001' AND sec_id = 1 AND semester = 'Fall' AND `year` = 2009
AND ID IN 
(SELECT ID
FROM student
WHERE `name` = 'Chavez')

# e.
DELETE FROM takes
WHERE course_id = 'CS-001'

DELETE FROM section
WHERE course_id = 'CS-001'

DELETE FROM course
WHERE course_id = 'CS-001'

#上面的顺序不能改变，因为takes的course_id外码依赖于section，
# section的course_id外码依赖于course，改变顺序会导致外码冲突

# f.
DELETE FROM takes
WHERE course_id IN
(SELECT course_id
FROM course
WHERE LOWER(title) LIKE '%database%')  

3.13

CREATE TABLE person
(driver_id VARCHAR(50),
`name` VARCHAR(50),
address VARCHAR(50),
PRIMARY KEY (driver_id))

CREATE TABLE car
(license VARCHAR(50),
model VARCHAR(50),
`year` INTEGER,
PRIMARY KEY (license))

CREATE TABLE accident
(report_number INTEGER,
`date` DATE,
location VARCHAR(50),
PRIMARY KEY (report_number))

CREATE TABLE owns
(driver_id VARCHAR(50),
license VARCHAR(50),
PRIMARY KEY (driver_id,license)
foriegn KEY (driver_id) REFERENCES person
foriegn KEY (license) REFERENCES car)

CREATE TABLE participated
(report_number INTEGER,
license VARCHAR(50),
driver_id VARCHAR(50),
damage_amount INTEGER,
PRIMARY KEY (report_number,license)
foriegn KEY (license) REFERENCES car
foriegn KEY (report_number) REFERENCES accident))

待续