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: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Lord Knight of the Black Rose Sent: Wednesday, April 27, 2005 1:48 AM To: pgsql-sql@postgresql.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 İf someone can help me about these stuff I will really apreciate. ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
