Database Systems - Assignment Example

Question A database request normally refers to a structured query language ment. A transaction is formed of one or more database requests. Mainly two types of transactions can be found namely local transactions and distributed transactions where distributed transaction differs on its ability to handle request from remote sites on a network. In these distributed databases systems, requests and transactions can further categorised as remote and distributed. Requests can be categorise as remote requests and distributed requests.

A remote request accesses data located in a single remote data processor site and queries can accesses that locations data only. A distributed request refers data from several different data processor sites. Each request can access data from many sites where a transaction access several data sites. Similar to requests, transactions can also be categorised as remote and distributed. A remote transaction is composed with several requests but accesses data in a single data processor site. A distributed transaction allows referring several local and remote data processor sites where an individual request can refer data in single location but the entire transaction will refer several sites to complete the transaction.

Question 2 Most of these problems occur due to data transformation incompatibilities and conventions used. With in the different divisions of an organization, operational data may vary in terms of how they are recorded or on the data type and structures used. For an example if we take a sales company the Customer service division may use ‘pending’,’ active’, ‘inactive’ and ‘cancelled’ but Audit division may use number tags such as 1, 2, 3, and 4. For same two divisions they may use different conventions for entering customer phone number to the database.

For an instance where the phone number can be entered as 091-3453489 by Audit division and the Customer services division enters it as 0913453489. In an educational institute may use different synonyms to represent academic staff designation. The Finance division may enter the full designation as Senior Lecturer, Lecturer, Probationary Lecturer, and Educational Assistant. The IT division may use a shorten form as SL, LE, PL, and EA for database data entry. References Ozsu, T.M. & Valduriez, P. (1999).Principles of Distributed Database Systems.

Prentice Hall Pubiucations, New York.