Scenario: Sweetbriar College is redesigning their course registration system [CR
ID: 3571846 • Letter: S
Question
Scenario: Sweetbriar College is redesigning their course registration system [CRS]. They plan for this system to be web-based, but first you need to model the main system behind the web interface. Here is a description of the interactions with the proposed CRS.
Faculty enter courses into the system, assign section numbers, instructors, dates, times, and classrooms for individual instances of a course. Students can browse available course-sections. Students or faculty advisors can register students for course-sections. Faculty can view a class list and enter grades for a course-section they are teaching. Students can view their course schedule and their grades for individual courses. The Registrar's office can view a student's history of courses and grades.
1. Using our Sweetbriar College scenario and the Object Class Model you developed, identify the object classes that require persistent storage.
2. Expand your Sweetbriar College Object Class Model by mapping the persistent object classes to RDBMS tables. Show the relationships and cardinality between the RDBMS tables.
3. Apply the normalization rules to the persistent objects that participate in the use case < Student registers for Course-Section>.
4. Expand your Sweetbriar College Object Class Model from Problem #2 by adding appropriate Data Access and Manipulation Classes. Remember to include the methods in each DAM class.
5. Using our Sweetbriar College scenario and your Use Case diagram of the system, identify the use cases that will require a user interface and briefly describe each interface.
Explanation / Answer
Without standardization, it becomes tough to handle and update the info, while not facing knowledge loss. Insertion, Updation and Deletion Anamolies square measure terribly frequent if info isn't Normalized. to grasp these associate degreeomalies allow us to take an example of Student table.
S_id S_Name S_Address Subject_opted
401 Adam Noida Bio
402 Alex Panipat Maths
403 Stuart Jammu Maths
404 Adam Noida Physics
Updation Anamoly : To update address of a student United Nations agency happens doubly or quite doubly in an exceedingly table, we are going to ought to update S_Address column altogether the rows, else knowledge can become inconsistent.
Insertion Anamoly : Suppose for a replacement admission, we've a Student id(S_id), name and address of a student however if student has not opted for any subjects nonetheless then we've to insert NULL there, resulting in Insertion Anamoly.
Deletion Anamoly : If (S_id) 401 has only 1 subject and briefly he drops it, after we delete that row, entire student record are going to be deleted together with it.
Normalization Rule
Normalization rule square measure divided into following traditional type.
First traditional type
Second traditional type
Third traditional type
BCNF
First traditional type (1NF)
As per 1st traditional type, no 2 Rows of knowledge should contain continuance cluster of data i.e every set of column should have a novel price, specified multiple columns can not be accustomed fetch an equivalent row. every table ought to be organized into rows, and every row ought to have a primary key that distinguishes it as distinctive.
The Primary key's sometimes one column, however typically quite one column may be combined to make one primary key. for instance think about a table that isn't in 1st traditional type
Student Table :
Student Age Subject
Adam 15 Biology, Maths
Alex 14 Maths
Stuart 17 Maths
In 1st traditional type, any row should not have a column within which quite one price is saved, like separated with commas. instead of that, we have a tendency to should separate such knowledge into multiple rows.
Student Table following 1NF are going to be :
Student Age Subject
Adam 15 Biology
Adam 15 Maths
Alex 14 Maths
Stuart 17 Maths
Using the primary traditional type, knowledge redundancy will increase, as there'll be several columns with same knowledge in multiple rows however every row as a full are going to be distinctive.
Second traditional type (2NF)
As per the Second traditional type there should not be any partial dependency of any column on primary key. It means for a table that has concatenated primary key, every column within the table that's not a part of the first key should rely on the complete concatenated key for its existence. If any column depends solely on one a part of the concatenated key, then the table fails Second traditional type.
In example of 1st traditional type there square measure 2 rows for Adam, to incorporate multiple subjects that he has opted for. whereas this is often searchable, and follows 1st traditional type, it's associate degree inefficient use of house. conjointly within the higher than Table in 1st traditional type, whereas the candidate key's , Age of Student solely depends on Student column, that is wrong as per Second traditional type. to attain second traditional type, it'd be useful to separate out the themes into associate degree freelance table, and match them up exploitation the coed names as foreign keys.
New Student Table following 2NF are going to be :
Student Age
Adam 15
Alex 14
Stuart 17
In Student Table the candidate key are going to be Student column, as a result of all different column i.e Age depends thereon.
New Subject Table introduced for 2NF are going to be :
Student Subject
Adam Biology
Adam Maths
Alex Maths
Stuart Maths
In Subject Table the candidate key are going to be column. Now, each the higher than tables qualifies for Second traditional type and can ne'er suffer from Update Anomalies. though there square measure a couple of advanced cases within which table in Second traditional type suffers Update Anomalies, and to handle those situations Third traditional type is there.
Third traditional type (3NF)
Third traditional type applies that each non-prime attribute of table should be smitten by primary key, or we are able to say that, there mustn't be the case that a non-prime attribute is set by another non-prime attribute. thus this transitive practical dependency ought to be faraway from the table and conjointly the table should be in Second traditional type.
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