
Concept explainers
Primary Key:
A Primary Key in a
Example:
Students in Universities are assigned a unique registration number.
Therefore, in a STUDENT database table, the attribute “reg_no” acts as primary key.
Foreign Key:
Foreign Key is a column in a relational database table which provides a relation between two tables. It provides a cross reference between tables by pointing to primary key of another table.
Example:
In STUDENT database table, the attribute “reg_no” acts as primary key and in COURSE database table in which the student selects his or her course, the same “reg_no” acts as foreign key for the STUDENT table.
Entity Integrity:
Entity Integrity is a
- The primary key of one database table row must not match the primary key of any other row present in the table.
- No component of primary key must be null.

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Chapter 3 Solutions
Database Systems: Design, Implementation, & Management
- Task 3. i) Compare your results from Tasks 1 and 2. j) Repeat Tasks 1 and 2 for 500 and 5,000 elements. k) Summarize run-time results in the following table: Time/size n String StringBuilder 50 500 5,000arrow_forwardCan you please solve this without AIarrow_forward1. Create a Vehicle.java file. Implement the public Vehicle and Car classes in Vehicle.java, including all the variables and methods in the UMLS. Vehicle - make: String model: String -year: int + Vehicle(String make, String, model, int, year) + getMake(): String + setMake(String make): void + getModel(): String + setModel(String model): void + getYear(): int + set Year(int year): void +toString(): String Car - numDoors: int + numberOfCar: int + Car(String make, String, model, int, year, int numDoors) + getNumDoors(): int + setNumDoors (int num Doors): void + toString(): String 2. Create a CarTest.java file. Implement a public CarTest class with a main method. In the main method, create one Car object and print the object using System.out.println(). Then, print the numberOfCar. Your printing result must follow the example output: make Toyota, model=Camry, year=2022 numDoors=4 1 Hint: You need to modify the toString methods in the Car class and Vehicle class!arrow_forward
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