Data Base Concept

Q.       Describe the major data management functions.

Ans.: Data management functions:

The Administer Database: responsible for maintaining the integrity of the Data Management database

Perform Queries: receives a query request from Access and Dissemination and executes the query to generate a result set} that is transmitted to the requester

The Generate Report: receives a report request and executes any queries or other processes necessary to generate the report then supplies the report to the requester

Receive Database Update: adds, modifies or deletes information in the Data Management persistent storage

Activate Request: maintains a record of subscription requests and periodically compares it to the contents of the archive to determine if all needed data is available. If needed data is available, this function generates a Dissemination Request which is sent to the Access. This function can also generate Dissemination Requests on a periodic basis.

Q.       Describe the rational database structure.               

Ans.: Relational database structure:

·         The relational database model uses a two – dimensional structure of rows and columns to store data. Tables can be linked by common key values.

·         Accessing data from relational databases may require complex joins of many tables and is distinctly non-trivial for untrained end-users.

·         When writing queries such as INSERT, DELETE and UPDATE on tables, the consequences of getting it wrong are greatly increased when they are employed on a live system environment.

·         A relational database consists of a collection of tables, each having a unique name. A row in a table represents a relationship among a set of values. Thus a table represents a collection of relationships.

·         There is a direct correspondence between the concept of a table and the mathematical concept of a relation. A substantial theory has been developed for relational databases.

Q.       Describe multidimensional database structure.   

Ans.: Multidimensional database structure:

·         Enhanced data representation and navigation by intuitive spreadsheet like views that are difficult to generate in relation database.

·         Easy to maintain because data is stored in the same way as it is viewed, so no additional computational overhead is required.

·         Data analysis and decision making is much easier through multidimensional database as compare relational database.

Q.       What are the object oriented database structures? Discuss with a diagram.           

Ans.: A database system that incorporates all the important object-oriented concepts

            Some additional features

·         Unique Object identifiers

·         Persistent object handling

            Object-oriented database consists: a. Abstract data types & b. Diagram discussion

            a. Abstract Data Types: Class definition, provides extension to complex attribute types

·         Encapsulation: Implementation of operations and object structure hidden

·         Inheritance: Sharing of data within hierarchy scope supports code reusability

·         Polymorphism: Multiple activities.

·         Operator overloading

b. Diagram discussion: The checking and savings account objects can both inherit the common attributes and operations of the parent bank account object. Such capabilities have made object-oriented database management system (OODBMS) popular in computer-aided design (CAD) and in a growing number of applications.