Experiment 04

Aim

To study and implement various data constraints in SQL

Theory

note

Write the following from the links provided:

• Not Null
• Unique
• Primary Key
• Foreign Key
• Check
• Default

Commands

CREATE TABLE Departments (
    DepartmentID INT PRIMARY KEY,
    DepartmentName VARCHAR(50) NOT NULL UNIQUE
);

CREATE TABLE Employees (
    EmployeeID INT PRIMARY KEY,
    FirstName VARCHAR(50) NOT NULL,
    LastName VARCHAR(50) NOT NULL,
    Email VARCHAR(100) UNIQUE,
    Age INT CHECK (Age >= 18),
    DepartmentID INT,
    Salary DECIMAL(10, 2) DEFAULT 30000.00,
    FOREIGN KEY (DepartmentID) REFERENCES Departments(DepartmentID)
);
DESCRIBE Employees;

Table

Draw the table that the following script will give as output(on the left-hand side of the record)

DESCRIBE Employees;

Conclusion

Successfully studied and implemented SQL data constraints