Where is the WEAK ENTITY in this ERD? and please explain what isthe weak entity? I don't see the weak entity.

If it's not in here then how to add a Weak entity and based onwhat?

Also how to determine the TOTAL Participation?

Could you please answer I need to understand these two parts

__________________________________________________________________________

Key points:

• Each patient?s personal details (name, address, and telephonenumber), and they are given an admission number.
• Patiets are then assigned to a particular ward.
• In each ward there are a number of doctors and nurses. (So,Ward: Doctor - 1: N)
• A patient will be treated by one doctor and several nurses.Which means (Doctor:Patient - 1:N) and (Nurse: Patient - N:N)
• Each doctor and nurse may be involved with severalpatients.(1:N)

So the ER diagram as required:

ER diagram:ER model is to represent the strucre of data by using entities andattributes and their reklations. ER diagram considers entities inreal world and relating with them. It is a graphical view.

Relational diagram:In Relational database model,the entities and relations arerepresented by using tables. Each table contains records andattribues.

ERD-Relational Schema

• If we have multi-valued attribute, make that attribute as newentity.
• In 1:1 Relationships, we are not considering relation asseperate entity. We add less priority table primary key as foreignkeyb of priority table.
• In 1:M relationships, we are not considering relation asseperate entity. We simply use primary key of one table as forignkey of another table.
• In M:M relationship, We need to create a relationship asseperate entity.

Now let us convert ER diagram to Relationaltables:

1) Relationship between Ward and Patient: As it contains 1:Nrelationship,we are adding primary key of Ward as foreign keyb ofPatient table.

Ward(Ward_Number,Ward_Name)Patient(Admission_Number,Name,Number,Address,Ward_Number)

2) Relationship between Doctor and Patient: As it contains 1:Nrelationship,we are adding primary key of Doctor as foreign keyb ofPatient table.

Doctor(Doctor_Id,Doctor_Name,Speciality)Patient(Admission_Number,Name,Number,Address,Ward_Number,Doctor_Id)

3) Relationship between Nurse and Patient: As it contains N:Nrelationship,we are adding relationship as another table.

Nurse(Nurse_ID,Nurse_Name)Assists(Admission_Number,Nurse_ID)Patient(Admission_Number,Name,Number,Address,Ward_Number,Doctor_Id)

4)Relationship between Ward and Doctor :As it contains 1:Nrelationship,we are adding primary key of Ward as foreign key ofDoctor table.

Ward(Ward_Number,Ward_Name)Doctor(Doctor_Id,Doctor_Name,Speciality,Ward_Number)

5) Relationship between Ward and Nurse: As it contains 1:Nrelationship,we are adding primary key of Ward as foreign key ofNurse table.

Ward(Ward_Number,Ward_Name)Nurse(Nurse_ID,Nurse_Name,Ward_Number)

So the final tables are:

Patient(Admission_Number,Name,Number,Address,Ward_Number,Doctor_Id)Ward(Ward_Number,Ward_Name)Nurse(Nurse_ID,Nurse_Name,Ward_Number)Assists(Admission_Number,Nurse_ID)Doctor(Doctor_Id,Doctor_Name,Speciality,Ward_Number)

Transcribed Image Text:

Admission Number Name Address Number DoctorID Speciality Doctor Name Patient Treates Doctor Admits Ward Ward_Name Works_In Nurse Ward Number NurselD Nurse_Name Admission Number Name Address Number DoctorID Speciality Doctor Name Patient Treates Doctor Admits Ward Ward_Name Works_In Nurse Ward Number NurselD Nurse_Name

Answer rating: 100% (QA)

Weak Entity A weak entity represents that entity in a schema whose existence depends u... View the full answer