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

Prepare an erd for the scenario, Question: (a) Prepare an ERD for the s...

Question: (a) Prepare an ERD for the scenario given below. (b) Convert the ER diagram produced in (a) above into its physical design. You have to choose an appropriate Pri

Define the concept of design documentation, Design Documentation  The ...

Design Documentation  The Design Document shall be an extension of Requirements Analysis Design. "The Design Document will comprise a revised and much more detailed descrip

What are the benefits of prepared statements, What are the benefits of prep...

What are the benefits of prepared statements and place holders? Parameter binding operations automatically handle escaping of characters Encourage Statement reuse

Cataloguing, differences between a classified catalog and a dictionary cata...

differences between a classified catalog and a dictionary catalog

Project operation, The PROJECT operation The project operation is used t...

The PROJECT operation The project operation is used to choose the records with specified attributes as discarding the others based on some related criteria. This is denotes as ∏

ER diegrams, How to draw an ER diagram to a finance companz

How to draw an ER diagram to a finance companz

Define the terms ddl and dml, Define the terms i) DDL ii) DML DDL: Data...

Define the terms i) DDL ii) DML DDL: Data base schema is particular by a set of definitions expressed by a special language known as a data definition language. DML: A data

Determine the strong and weak entity, Determine the Strong and Weak Entity ...

Determine the Strong and Weak Entity Based on the method of foreign key, there might be arise a situation when we have to relate an entity having a primary key of its own and a

Explain saving derived attributes to avoid re-computation, Saving Derived A...

Saving Derived Attributes to Avoid Re-computation   As discussed, "redundancy means duplication of exact data". But, if multiple copies of same data are present in the system,

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