定義主鍵約束（每乙個表必須有乙個主鍵列）
create table student
(id int primary key,
name varchar(40)
);定義主鍵自動增長
create table student
(id int primary key auto_increment,
name varchar(40)
);定義唯一約束
drop table student;
create table student
(id int primary key auto_increment,
name varchar(40) unique
);定義非空約束
drop table student;
create table student
(id int primary key auto_increment,
name varchar(40) unique not null
);定義外來鍵約束
create table husband
(id int primary key,
name varchar(40)
);create table wife
(id int primary key,
name varchar(40),
husband_id int,
constraint husband_id_fk foreign key(husband_id) references husband(id)
);一對多或多對一的物件存到資料庫時，表的設計方案
部門和員工
create table department
(id int primary key,
name varchar(40)
);create table employee
(id int primary key,
name varchar(40),
salary decimal(8,2),
department_id int,
constraint department_id_fk foreign key(department_id) references department(id)
);多對多物件的表的設計（老師和學生）
create table teacher
(id int primary key,
name varchar(40),
salary decimal(8,2)
);create table student
(id int primary key,
name varchar(40)
);create table teacher_student
(teacher_id int,
student_id int,
primary key(teacher_id,student_id),
constraint teacher_id_fk foreign key(teacher_id) references teacher(id),
constraint student_id_fk foreign key(student_id) references student(id)
);一對一的物件的資料庫設計
create table person
(id int primary key,
name varchar(40)
);create table idcard
(id int primary key,
city varchar(40),
constraint id_fk foreign key(id) references person(id)
);自連線的表
create table person
(id int primary key,
name varchar(40),
parent_id int,
constraint parent_id_fk foreign key(parent_id) references person(id)
);
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主鍵 表和外建表是相對來說的，簡單的說就是乙個表的 主鍵是另外一張表的 外來鍵。例如 class 班級表主要字段如下 classid primary key 主鍵 班級id classname 班級名稱 studen 學生表主要字段如下 stuid primary key 主鍵 學生id stuna...
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oracle select o.obj as objectid,o.name as tablename,oc.name as constraintname,decode c.type 1,c 2,p 3,u 4,r 5,v 6,o 7,c as constrainttype,col.name as ...