From: Lord Knight of the Black Rose <xdarknessx82@hotmail.com>
To: pgsql-sql@postgresql.org
Subject: can someone jelp me on this?
Date: Tue, 26 Apr 2005 20:18:01 +0000
Message-ID: <BAY101-F111203A36D0EA8D7D1F9BDD2210@phx.gbl> (raw)
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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To: pgsql-sql@postgresql.org
Cc: xdarknessx82@hotmail.com
Subject: Re: can someone jelp me on this?
In-Reply-To: <BAY101-F111203A36D0EA8D7D1F9BDD2210@phx.gbl>
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