Consider the following relational schema, DDL statements and tables. Show the st

Question

Consider the following relational schema, DDL statements and tables. Show the status of the above tables after each of the following operations:

Inserting a new employee: 30, F, 6, 9 into the Table EMPLOYEE. If it is rejected, explain

EMPLOYEE( EmployeeID, EmployeeName, SupervisorID, Department ID)

PROJECT (ProjectID, EmployeeID)

DEPARTMENT( Department ID, DepartmentName)

CREATE TABLE EMPLOYEE

( EmployeeID          INT PRIMARY KEY,

  EmployeeName   VARCHAR(50) NOT NULL,

  SupervisorID INT DEFAULT 9,

  DepartmentID   INT,

  FOREIGN KEY (SupervisorID) REFERENCES EMPLOYEE (EmployeeID)

  ON DELETE SET NULL ON UPDATE SET DEFAULT

);

CREATE TABLE PROJECT (

ProjectID    INT PRIMARY KEY,

EmployeeID INT DEFAULT 9,

FOREIGN KEY (EmployeeID) REFERENCES EMPLOYEE (EmployeeID)

  ON DELETE SET NULL   );

CREATE TABLE DEPARTMENT(

DepartmentID INT PRIMARY KEY,

DepartmentName   VARCHAR(50)

);

EMPLOYEE EmployeeID EmployeeName SupervisorID DepartmentID NULL PROJECT ProjectID EmployeeID DEPARTMENT DepartmentID DepartmentName

Explanation / Answer

If you have any doubts, please give me comment...

INSERT INTO EMPLOYEE VALUES(30, 'F', 6, 9);

By executing this query, you will get error because of foreign key constraint fails. We don't have department ID with 9 in Department table.

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