agree!
Student(name, Student_ID(primary key))
belongsto(Student_ID,Class_ID) primary key(Student_ID + Class_ID)
class(Class_ID(primary key),address)
Student(name, Student_ID(primary key))
belongsto(Student_ID,Class_ID) primary key(Student_ID + Class_ID)
class(Class_ID(primary key),address)
tab2-->班级信息(banji_id,……)
tab3-->班级-学生关系表(banji_id,xuesheng_id)
Student(name, Student_ID(primary key))
belongsto(Student_ID,Class_ID)
primary key(Student_ID + Class_ID)
foreign key 1. Student_ID
2. Class_ID
class(Class_ID(primary key),address)
和T-SQL是否一样?还是和外键约束一样,需要另外说明?
请推荐一本有关的SQL语法书籍!
e-book,tell me if u want,ftp to u
在看Oracle 8 PL/SQL 时候,好像说支持布尔类型的嘛!