Database Reference
In-Depth Information
◾
For the
classroom
and
building
objects, the classroom number and capacity are of the
integer type. he building name can be deined as character strings. here are few changes
in classrooms and buildings. herefore, the data increase rate is very low.
◾
For the
faculty
object, the faculty ID can be the integer type, and the irst name and last
name should be character strings. he faculty is relatively stable, so its growth rate is low.
◾
For the
class time
object, time blocks and week days are a set of predeined character strings.
he values for these objects are ixed, so there is almost no data growth for this object.
◾
For the
semester
object, the data type for the semester is deined as character strings. Since
semester values need to be accumulated each year, there will be some data growth for this
object.
Identify relationships among objects
: Our next task is to ind out how the objects are related
to each other in a business process. Since the class object is related to course, class time, semes-
ter, classroom, instructor, and student, we have the relationships Class-Course, Class-Student,
Class-Faculty, Class-Time Block, Class-Week Day, Class-Semester, and Class-Classroom. From
the interviews, we know that the faculty object is related to the student object. We should have the
relationship Faculty-Student. Also, by examining the class schedule, we can see that the relation-
ship Classroom-Building should also be included.
Identify business rules imposed on objects
: he university has some rules related to the objects
in this database project. hese rules will have an impact on the relationships among the objects.
By examining the course catalog, we list the following related rules for our database objects.
◾
he minimum enrollment for each class is 10 students. If an undergraduate class is
<
10 students
enrolled, the class will be canceled.
◾
he maximum number of students for a class will depend on the classroom capacity.
◾
A course may or may not have a prerequisite. Some courses can have the same prerequisite
and several prerequisites can be required for one course.
◾
Credits for each course range from 1 to 12.
◾
A new student may not be assigned an advisor immediately. herefore, a student may or may
not have an advisor in the database. Each student can only have one advisor and each faculty
member can have zero, one, or many advisees.
From the class schedule, the following rules can be observed:
◾
Two classrooms may have the same number if they located in diferent buildings. herefore,
when listing classroom information in the class schedule, we are required to attach building
names to classrooms.
◾
Sometimes, one class may need two classrooms. For example, a computer science class may
need a classroom for lecture and another classroom for lab.
◾
A classroom can hold multiple classes scheduled for diferent time blocks.
◾
he teaching load for a full-time faculty member is four classes per semester. For example,
Smith is teaching multiple classes in the class schedule print out.
◾
Sometimes, a class may be taught by more than one professor. For example, e-commerce is
taught by both Smith and Lee; each teaches the topics from their own research.
◾
A building may have one or more classrooms.
◾
Each classroom should have one class at a time. We cannot schedule two classes in the same
classroom at the same time.
