Task 1: Designing an Entity-Relationship Model
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Task 1: Designing an Entity-Relationship Model
Exercise Central Study
Exercise Central ( EC) is an Australian fitness company. The following are the requirements for managing data about staff, clients, and exercise plans for EC.
Exercise Plans
EC is responsible for managing exercise plans for customers in Australia. Each exercise plan has a unique plan number and also has a description such as ' building core strength' . The system keeps track of various general exercises performed as part of an exercise p l a n, recording the uni q ue name of the exercise, its description, and the muscl e groups that it targets. For example a ‘squat' which involves ' lowering and raising your body by bending your knees on a single spot' which targets your ' legs' and your 'core' muscle groups.
Staff
Staff develop specialised exercise p l a n s that are an instance of an exercise and plan with a specific intensity, for example a ' high' intensity squat ( which is part of building core strength) . It records the number of repetitions, sets, intervals and number of days per week that the exercise should be performed (for a given intensity level). For example, a low intensity squat exercise plan might have lower repetition, sets, intervals and days per week, than a high intensity squat plan.
A staff member can develop many such plans, but only one staff member is responsible for developing the plan. Specialised exercise plans can be managed by many different staff ( not necessarily the staff member who developed them), and a staff member can manage many such plans.
The system records the staff members id, name, and speciality.
Course
Customers can enrol in many courses, with each course composed of several specific exercise plans (eg a low intensity squat plan and a high intensity bicep curl plan) . Plans can be a part of many courses. A course has a course id, a fee and a duration (in weeks).
Customer
Each Customer has a unique number and has a name, address and phoneNo. The date that customers begin each course is recorded.
Based on the given description, model the given business rules, and present your model as an Entity- Relationship ( ER) diagram. Carefully state any assumptions that you make. In your ER diagram, you must properly denote all applicable concepts, including weak or strong entities, keys, composite or multi- valued attributes, relationships and their cardinality and participation constraints.
If you cannot represent any of this information in the ER model, clearly explain what limitations in the ER model restrict you from representing your model.
You must use UML notation and the diagramming tool Lucidchartto draw your diagram. Your diagram must be drawn to a high standard with minimal clutter. You are not required to map the ER model to relational model.
A special note: This is an open- ended question with many different models that can be derived. Your model is assessed based on how accurately it represents business rules described above.
Task 2: Designing an Entity-Relationship Model
Part A: Initial Design
Quick Service Case Study
Quick Service is an Australian vehicle repair center.
You are asked to design a database for managing the vehicle service details. Requirements for the database are as follows:
Vehicles are brought in for service. For each vehicle the database records the registration number, make, model and year.
The date, time, duration and fee of the service are also recorded, along with the details of the mechanic who performed the service (employee id and name).
During the service a log of issues that were identified are recorded. For each issue, the name, description, and outcome are stored.
For each issue identified, the system records the parts that were installed. The parts have a partNo, supplier, description, and cost. Note that the same part may be available from more than one supplier. The same part may be used as part of different issues.
Based on the given description, model the business rules of Quick Service, and present your model as an Entity- Relationship ( ER) diagram. Carefully state any assumptions that you make. In your ER diagram, you must properly denote all applicable concepts, including weak or strong entities, keys, composite or multi-valued attributes, relationships and their cardinality and participation constraints.
If you cannot represent any of this information in the ER model, clearly explain what limitations in the ER model restrict you from representing your model. Avoid introducing unnecessary artificial keys.
You must use UML notation and the diagramming tool Lucidchartto draw your diagram. Your diagram must be drawn to a high standard with minimal clutter. You are not required to map the ER model to relational model.
A special note: This is an open- ended question with many different models that can be derived. Your model is assessed based on how accurately it represents business rules described above.
Part B: Client Adjustments
After presenting your ER model to Quick Service management, you are asked if it can be used to perform the following additional tasks.
Several mechanics may be involved in the service of a vehicle. The system needs to be able to identify which mechanic installed each part and resolved each issue during the service.
The system needs to record not just the cost of parts but also the installation fee.
Some mechanics have higher seniority and may supervise other mechanics. Mechanics cannot have more than one supervisor. The date when they began supervising others is recorded.
The same issue could come up with a different description or outcome during various services of vehicles.
For each one of the tasks specified above, explain how your ER diagram is supporting it. If it is not possible to achieve any of the tasks above given your current design, state why, modify the model, provide the modified ER diagram (in addition to your original ER diagram), and explain how the new model achieves the missing requirements.
Task 3: Mapping an ER Model to a Relational Database Schema
Consider the following ER diagram, which shows aspects of a construction project management system.
You are requested to map the above ER diagram into a relational database schema. Show every step of the mapping. No marks are awarded to the final schema if you do not show the partially built schema at the end of each step. Clearly indicate the primary key (underlined) and foreign keys (with an asterisk) in each relation.
Task 4: Relational Database Model
This section contains the schema and a database i n s t a n c e for the E m p l o y e e database that stores employee data for an organisation. The data includes items such as personal info (e.g. , name, phone, salary) , departments of the organisation (e.g., name and location of each department, who the manager is) , jobs (e. g. , titles, salary range) , and a history for past contracts with each employee. A database instance is shown in Figure 2 followed by the database schema.
The database schema is shown below, and the meaning of most attributes is
self-explanatory. “Job History” is simplified as “JobHistory” . Primary keys are underlined, and foreign keys are annotated with a *.
Employees (employee_id, first_name, last_name, phone_number, hire_date,
empjob_id, salary, department_id)
Departments (department_id, department_name, manager_id*, location_id*)
Jobs (job_id, job_title, min_salary, max_salary)
Locations (location_id, street_address, postal_code, city, state_province,
country_id*)
Countries (country_id, country_name)
JobHistory (employee_id*, start_date, end_date, job_id*, department_id*)
The following table further clarifies the connection between the keys across multiple tables.
The following questions must be answered based on the given database schema and instance. Where explanation is required, each answer should be a SHORT passage of at most several lines.
QUESTION 4. 1 : Does the database schema ensure that there is a manager associat ed with each depart ment? Explain your answer.
Questions 4.2 : What foreign key constraints are missing from Figure 3 ? Write down the missing constraints in the format shown in figure 3. Show the updated schema for the corresponding relations.
QUESTION 4.3: The IT Services department has recently changed to have two sub-departments (i.e., IT Support, and Software Devlopment) . Now, each sub-department is supposed to have a separate manager. Additionally, the managers of all IT Services sub-departments now must report to a single Director (i.e., “Director of Support Services”) . Temporarily and until the new managers are hired, Adam Jones has been appointed to the management of both
sub- departments as well to the single role of Director of Support Services. His salary range is between $130,000 and 160,000.
The following SQL statements are intended to record all the changes required in the database instance. Will they work? If they are sufficient to achieve the requirements specified above, explicitly mention they are sufficient. If there are any shortcomings, identify them and briefly justify your answer.
UPDATE Departments SET department_name= ' IT Support ' WHERE
department_ id= 1 ;
INSERT INTO Departments VALUES (4, 'Software Development ', 12,
10);
QUESTION 4.4: The employee named Jonny Deans changed his job to
become a Senior Programmer on 6/06/2020. The following SQL
statement intends to make the required changes to reflect Jonny’s
promotion.
UPDATE Employees SET empjob_id=45 , hire_date= 6 /0 6/2 02 0 WHERE
empjob_id=33 ;
Explain if there any issues with the outcome of the update and how it should be fixed? After running the above query, consider the request “find all the past contracts that Jonny Deans used to have” . Can this request be completed using the given database schema and after the above statement is run? If yes, explain how the request can be answered. If no, explain what is missing and how it should be fixed.
QUESTION 4.5: Explain what the result of executing the following SQL
statement on the data base i nstance will be . DELETE FROM
LOCATIONS WHERE location id= 1 0 ;
Identify all changes that must be completed to allow this to successfully execute.
QUESTION 4.6: Write an SQL statement to create the JobHistory table including all the constraints, assuming all the tables that JobHistory depends on already exist in the database. Make reasonable assumptions for the data type associated with each field. Your SQL statement must be valid for SQLite Studio environment and free of any errors.
QUESTION 4.7: Write an SQL statement to create the Jobs table including all the constraints, assuming all the tables that Jobs depends on already exist in the database. Make reasonable assumptions for the data type associated with each field. Your SQL statement must be valid for SQLite Studio environment and free of any errors.
QUESTION 4.8: On ‘01/01/2021’ Adam Smith is rehired with a new salary of $90,000. You are asked to update the given database instance so that it includes ALL relevant changes required to store this consistently across all realations. Your SQL statement must be valid for SQLite Studio environment, free of any errors, and compatible/consistent with existing data in the instance in Figure 2.
2023-04-06