Re: can someone jelp me on this?

Hi,

Your mail just contain the database studcture and project spec. and nothing about the problem. Please let me know what help you are looking for?

Regards,
R.Muralidharan

-----Original Message-----
From: pgsql-sql-owner(at)postgresql(dot)org
[mailto:pgsql-sql-owner(at)postgresql(dot)org]On Behalf Of Lord Knight of the
Black Rose
Sent: Wednesday, April 27, 2005 1:48 AM
To: pgsql-sql(at)postgresql(dot)org
Subject: [SQL] can someone jelp me on this?

hey guys I have a question that I couldnt maneged to solve for the last 4
days. Im kinda new to these stuff so dont have fun with me if it was so
easy. Ok now heres the question.

create table student
(student_id int not null,
student_name varchar(25),
student_affiliation int,
student_password varchar(20),
student_email varchar(30),
student_phone varchar(12),
student_address varchar(50));

create table instructor
(instructor_id int not null,
instructor_name varchar(25),
instructor_affiliation int,
instructor_password varchar(20),
instructor_email varchar(30),
instructor_phone varchar(12),
instructor_address varchar(50));

create table course
(course_id int not null,
course_name varchar(25),
course_sections int,
course_description varchar(50));

create table class
(course_id int not null,
class_section int not null,
class_strength int,
class_date date,
class_time time);

create table student_class
(course_id int not null,
class_section int,
student_id int not null);

create table instructor_class
(course_id int not null,
class_section int,
instructor_id int not null);

insert into student (student_id, student_name) Values (1, 'Marge Trechle');
insert into student (student_id, student_name) Values (2, 'Todd Relve');
insert into student (student_id, student_name) Values (3, 'Beth
Schavinsky');
insert into student (student_id, student_name) Values (4, 'Thomas
Newburry');
insert into student (student_id, student_name) Values (5, 'Geoff Hamilton');
insert into student (student_id, student_name) Values (6, 'Cindy Crumple');
insert into student (student_id, student_name) Values (7, 'Keith Snyder');
insert into student (student_id, student_name) Values (8, 'Belinda Myers');
insert into student (student_id, student_name) Values (9, 'Hope Wilson');
insert into student (student_id, student_name) Values (10, 'Icculus McMan');
insert into student (student_id, student_name) Values (11, 'Mary Calahan');

insert into instructor (instructor_id, instructor_name) values (1, 'Norm
Salvadori');
insert into instructor (instructor_id, instructor_name) values (2, 'Terry
Smith');

insert into course (course_id, course_name) values (1, 'Wetlands Critters');
insert into course (course_id, course_name) values (2, 'Ocean Ecosystems');
insert into course (course_id, course_name) values (3, 'Endangered
Habitats');

insert into class (course_id, class_section) values (1,1);
insert into class (course_id, class_section) values (1,2);
insert into class (course_id, class_section) values (2,1);
insert into class (course_id, class_section) values (3,1);

The values inserted into the database can change and more entries can be
inserted and in this situation I have to write the constraints according to
these criteria:
1. A COURSE may consist of one or more CLASSes
2. An INSTRUCTOR may teach one or more CLASSes
3. A STUDENT may enroll in many CLASSes
4. A STUDENT can take more than one CLASS, and each CLASS contains many
STUDENTS
5. A CLASS is taught by only one INSTRUCTOR, but an INSTRUCTOR can teach
many CLASSes
6. A COURSE consists many CLASSes, while each CLASS is based on one
COURSE, so there is a one-to-many relationship between COURSE and
CLASS
7. A STUDENT may not enroll himself/herself for two CLASSes of the same
course
8. An INSTRUCTOR may not teach two CLASSes of the same COURSE

Ýf someone can help me about these stuff I will really apreciate.

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