msyql筆記

CREATE TABLE class (
  cid int(11) NOT NULL AUTO_INCREMENT,
  caption varchar(32) NOT NULL,
  PRIMARY KEY (cid)
) ENGINE=InnoDB CHARSET=utf8;

CREATE TABLE student(
  sid int(11) NOT NULL AUTO_INCREMENT,
  gender char(1) NOT NULL,
  class_id int(11) NOT NULL,
  sname varchar(32) NOT NULL,
  PRIMARY KEY (sid),
  KEY fk_class (class_id),
  CONSTRAINT fk_class FOREIGN KEY (class_id) REFERENCES class (cid)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;


CREATE TABLE teacher(
  tid int(11) NOT NULL AUTO_INCREMENT,
  tname varchar(32) NOT NULL,
  PRIMARY KEY (tid)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE course(
  cid int(11) NOT NULL AUTO_INCREMENT,
  cname varchar(32) NOT NULL,
  teacher_id int(11) NOT NULL,
  PRIMARY KEY (cid),
  KEY fk_course_teacher (teacher_id), #建立索引並加約束
  CONSTRAINT fk_course_teacher FOREIGN KEY (teacher_id) REFERENCES teacher (tid)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE score (
  sid int(11) NOT NULL AUTO_INCREMENT,
  student_id int(11) NOT NULL,
  course_id int(11) NOT NULL,
  num int(11) NOT NULL,
  PRIMARY KEY (sid),
  KEY fk_score_student (student_id),
  KEY fk_score_course (course_id),
  CONSTRAINT fk_score_course FOREIGN KEY (course_id) REFERENCES course (cid),
  CONSTRAINT fk_score_student FOREIGN KEY (student_id) REFERENCES student(sid)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO class VALUES
(1, '三年二班'), 
(2, '三年三班'), 
(3, '一年二班'), 
(4, '二年九班');

INSERT INTO student VALUES
(1, '男', 1, '理解'), 
(2, '女', 1, '鋼蛋'), 
(3, '男', 1, '張三'), 
(4, '男', 1, '張一'), 
(5, '女', 1, '張二'), 
(6, '男', 1, '張四'), 
(7, '女', 2, '鐵錘'), 
(8, '男', 2, '李三'), 
(9, '男', 2, '李一'), 
(10, '女', 2, '李二'), 
(11, '男', 2, '李四'), 
(12, '女', 3, '如花'), 
(13, '男', 3, '劉三'), 
(14, '男', 3, '劉一'), 
(15, '女', 3, '劉二'), 
(16, '男', 3, '劉四');

INSERT INTO teacher VALUES
(1, '張磊老師'), 
(2, '李平老師'), 
(3, '劉海燕老師'), 
(4, '朱雲海老師'), 
(5, '李傑老師');

INSERT INTO course VALUES
(1, '生物', 1), 
(2, '物理', 2), 
(3, '體育', 3), 
(4, '美術', 2);


INSERT INTO score VALUES
(1, 1, 1, 10),
(2, 1, 2, 9),
(5, 1, 4, 66),
(6, 2, 1, 8),
(8, 2, 3, 68),
(9, 2, 4, 99),
(10, 3, 1, 77),
(11, 3, 2, 66),
(12, 3, 3, 87),
(13, 3, 4, 99),
(14, 4, 1, 79),
(15, 4, 2, 11),
(16, 4, 3, 67),
(17, 4, 4, 100),
(18, 5, 1, 79),
(19, 5, 2, 11),
(20, 5, 3, 67),
(21, 5, 4, 100),
(22, 6, 1, 9),
(23, 6, 2, 100),
(24, 6, 3, 67),
(25, 6, 4, 100),
(26, 7, 1, 9),
(27, 7, 2, 100),
(28, 7, 3, 67),
(29, 7, 4, 88),
(30, 8, 1, 9),
(31, 8, 2, 100),
(32, 8, 3, 67),
(33, 8, 4, 88),
(34, 9, 1, 91),
(35, 9, 2, 88),
(36, 9, 3, 67),
(37, 9, 4, 22),
(38, 10, 1, 90),
(39, 10, 2, 77),
(40, 10, 3, 43),
(41, 10, 4, 87),
(42, 11, 1, 90),
(43, 11, 2, 77),
(44, 11, 3, 43),
(45, 11, 4, 87),
(46, 12, 1, 90),
(47, 12, 2, 77),
(48, 12, 3, 43),
(49, 12, 4, 87),
(52, 13, 3, 87);

1.KEY fk_course_teacher (teacher_id),表示建立索引fk_course_teacher，類型是normal。並添加約束
2.在關聯表的時候須要先建立好。
3.在刪除的時候要先刪除關聯表，不然出錯。
4.CONSTRAINT fk_class FOREIGN KEY (class_id) REFERENCES class (cid) ，添加外鍵約束FOREIGN KEY (class_id) REFERENCES class (cid)表示本表的class_id字段外聯class表的cid字段。class若是不提早建立好就出出錯。
後續。。。