1.What do you mean by life cycle concept?

System are created by a dynamic process that moves through a series of stages, or phases. The concept of life cycle has evolved to describe the relationship between these phases. Like most system, the life cycle of a computer based system exhibits distinct phases. There are
    1.    The requirement analysis
    2.    Design
    3.    Coding
    4.    Testing
    5.    Implementing
    6.    Maintenance

2.    What do you mean by a system? Explain.

A system is an orderly grouping of interdependent components linked together according to a plan to achieve a specific objective. Components means physical parts (engines, wings of aircraft, wheels of a car), managerial steps (planning, organizing, directing, controlling) or a subsystem in a multilevel structure.

3. What are the characteristics of a system?

Some characteristics that are present in all systems are as follows.

    1.    Organization – implies structure and order i.e. arrangement of components to achieve objectives.
    2.    Interaction – Manner in which each component functions with other components of the system.
    3.    Interdependence – parts of the organization or computer system depend on one another.
    4.    Integration- the holism of system to achieve the central objective by sharing the parts or location.
    5.    Central objective – should have a real or stated objective.
   

4.    Explain who is a system Analyst?

System analyst is the individual who is responsible for the performance of system analysis for all, or a portion of, the phases of the life cycle of a business system. In effect the analyst is a life cycle manager.

5. Importance of system Analysis and Design (SAD)?

It is very important to have the system are studied before it is actually being designed and new system is developed for increased office productivity. At present, computers and their applications significantly affect almost every aspect of modern business. Industrial and financial institutions will be dominated by information systems with capabilities for beyond those visible today. Therefore, the study of system analysis, which is a structured process for designing and developing effective business information system, is becoming increasingly important.

6. Explain what is Entity Relationship Model?

The ER data model is based on a real world that consists of a collection of basic objects (entities) and of relationships among these objects. An entity is a ‘thing’ or ‘object’ in the real world that is distinguishable from other objects. For example, Each person is an entity, and bank accounts can be considered to be entities. Entities are described in  a database by  a set of attributes.

7. What do you mean by an entity?

Entity also called a data aggregate, something of interest to the user about which to collect or store data, represents a number of data elements. For example, the attributes account number and balance describe one particular account in a bank.

8. What do you mean by client server Database (CSDB)?

The term “client/server” means any system that splits its data processing between two distinct components- the client and the server. Similarly, the client/server database also splits the database processing between two system-the client PC which runs the database application and the database server which runs all or part of the actual DBMS.

9. What is a Database system?

A database system is nothing more than a computer – based record keeping system i.e., a system whose overall purpose is to record and maintain information. The information concerned can be anything that is deemed to be of significant to the organization or that may be necessary to the decision making process involved in the management of that organization.

10. What is a Data Base? Explain?

A Database is a single organized collection of structured data, stored with minimum duplication of data items so as to provide a consistent and controlled pool of data. It is a concept of file organization, it consists of related data stored together so that groups of data items can be easily accessed or retrieved by those who need them. The data are integrated so that individual datum can  be accessed in a variety of ways.

11. What is a Data Model?

The structure of a database is the concept of a data model. A data model is a collection of conceptual tools for describing data, data relationship, data semantics, consistency and constraints. They are in three different groups as follows.
   
     1.    Object Based logical Model.
     2.    Physical Data model
     3.    Record Based logical model.

12. Explain about Hierarchical Model?

The hierarchical DBMS represents data as tree structure, composed of hierarchy of data records. It is similar to network model in the sense that data and relationships among data are represented by records and links respectively. The simple structure of the hierarchical database was not suitable when the data had a complex structure.

13. Explain about Network Model?

Data in the Network model are represented by collection of records and relationships among data are represented by links, which can be viewed as pointers. The hierarchical data model was modified by allowing records to have multiple parent child relationships. These relationships are known as sets in the network data model. The records in the database are organized as collection of arbitrary graphs.

14. Explain about Relational Model?

The Relational model uses a simple collection of two-dimensional tables to represent even the most complex hierarchical and network databases, otherwise called RDBMS (Relational Database Management System).

15.What is mean by Data Normalization.

Normalization is a formal process of developing data structure in a manner that eliminates redundancy and promotes integrity. Data normalization is a corner stone of the relational theory. Many people do not considered a set of data structures to be relational unless it is fully normalized. There are different steps to Data Normalization, which are called the normal forms.

16. What do you mean by Attributes?

Attributes are some properties of interest (or characteristics) that further describe the entity such as height, weight and date of birth in case of a person and code and name in case of accounts. An entity has a value for each of its attributes, which is the data stored in the database.

17. Explain the difference between composite and simple attributes?

The composite attributes can be divided into smaller sub- parts to represent some more basic attributes with independent meanings. The simple attributes cannot be further sub-divided. For example, Name of a person that is normally sub divided into first name, middle name and last name is a composite attribute. Height of a person is a simple attribute as it is devoid of further sub -division.

18.Explain the difference between single valued and multi valued attributes?

An attribute with a single value for an entity is single valued as opposed to those which multiple values. For example, height of a person is single valued attribute while qualifications of that person are a multi valued attribute.

19. Explain the difference between stored and Derived Attributes?

Two or more attributes may be related in such a way that one or more becomes basic while the other becomes dependent on that  basic attribute. For example, date of birth of a person is a stored attribute while age of that person is derived attribute.

20. What is Null value?

Absence of a data item is represented by a special value called null value. There are three situation which may require the use of null values.

1. When a particular attribute does not apply to an entity
2. value of an attribute is unknown, although it exists.
3. unknown because it does not exist.