Trigger , Database Management System

Assignment Help:

Flights(FlightNo, DeptDateTime, Origin, ArrivalDateTime, Destination, Capacity, SoldSeats) Tickets(FlightNo, Seat, CustID)

Where
- flightNo is the PK of the flights table
- DeptDateTime holds the date and time of the flights departure
- Origin holds the airport code (e.g. RKE) of the flights origin
- ArrivalDateTime holds the date and time of the flights arrival
- Destination holds the airport code (e.g. ATL) of the flights destination
- Capacity is the number of passenger seats the flight can hold
- SoldSeats is the number of seats that are currently sold

- FlightNo+Seat is the PK of the Tickets Table
- FlightNo in the Tickets Table is an FK referencing the Flights Table
- Seat is the seat assigned to that ticket (e.g. 7B)
- CustID is the ID number of the customer that is assigned to that seat

Write a trigger or triggers that:
- increments the SoldSeats field when a ticket is inserted
- raises an exeception when an attempt to insert a ticket occurs
  if the flight is already sold out
- decrements the SoldSeats field when a ticket is deleted

To provide appropriate transaction control your trigger should lock the associated flight row in the flights table before attempting to update the SoldSeats field.

Add sample data and test your triggers.

Have your triggers finished with some sample data entered by the start of class on November 16th.


Related Discussions:- Trigger

Physical dbms architecture, PHYSICAL DBMS ARCHITECTURE  The physical ...

PHYSICAL DBMS ARCHITECTURE  The physical architecture defines the software components used to process and enter data, and how these software components are related and interc

What is known as heap file organization, What is known as heap file organiz...

What is known as heap file organization? In the heap file organization, any record can be placed anywhere in the file where there is space for the record. There is no ordering

What is functional dependency, What is Functional Dependency? A Functi...

What is Functional Dependency? A Functional dependency is shown by X Y among two sets of attributes X and Y that are subsets of R specifies a constraint on the possible tuple

Domain constraint, Domain Constraint It shows that each attribute in a ...

Domain Constraint It shows that each attribute in a relation has to contain an atomic value only from the corresponding domains. The data types associated with commercial RDBMS

How does the two phase protocol ensure serializability, How does the two ph...

How does the two phase protocol ensure serializability in database schedules?   Ans:  A transaction is termed to follow the two-phase locking protocol if all locking operations

ERD, #question.ERD of any car

#question.ERD of any car

Define dba database administrator, Define DBA database administrator? ...

Define DBA database administrator? DBA : A database administrator (DBA) is a person who is responsible for the environmental aspects of a database. In common, these involves:

Implementing a data warehouse, (a) Data warehouse can be defined as "a sub...

(a) Data warehouse can be defined as "a subject-oriented, integrated, time-variant, non-volatile collection of data" in support of management's decision making process. Explain ea

#cursor, #what is cursor its uses ? Explain it

#what is cursor its uses ? Explain it

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd