Chapter 6, Problem 1RQ

Explanation of Solution

Problems of managing data resources in a traditional file environment

• The traditional file environment creates many problems of managing data resources.
• The problems include data redundancy and inconsistency, program data dependence, inflexibility, poor security and lack of data sharing and availability.
• These problems can be solved easily through the implementation of a database management system.
• A database management system is a software package designed for defining, manipulating, retrieving and managing data in a database.

Explanation of Solution

Components in the data hierarchy

The components in the data hierarchy include database, file, record, field, byte and bit.

Database

• A database is a collection or group of related files that belong to an organization or firm.
• It is a structured set of data held in a computer.
• It is a data structure that stores organized information.

File

• A file is a collection or group of company records that contain specific information.
• It is a common storage unit in a computer.
• It is a sequence of records stored in binary format.

Record

• A record is the collection of a group of related fields.
• A record of an employee includes personal information, work history, job accomplishments, and salary information.
• It is an object that can contain one or more values.

Field

• A field is a grouping of characters that can take the form of a word, a group of words, or a number.
• It is the set of data values of the same data type.
• Most databases allow fields to hold complex data like pictures, entire files and so on.

Byte

• A byte is a set of bits.
• A byte would be a single character that represents a letter, number or symbol.
• It is a unit of digital information that consists of eight bits.

Bit

• A bit is the smallest unit of data a computer can handle.
• A bit is either 0 or 1.
• It is the basic unit of information in information theory, computing and digital communications.

Explanation of Solution

Significance of entity, attribute and key fields

Entity

• Entity is a mass block for building the data collected about person, place, event or thing.
• Entities represent attributes with multiple instances.
• Hence entity is about collection of data regarding person, place or thing.
• Examples of entities are patient, musician and so on.

Attribute

• An attribute is the property of an entity.
• It has the information about entity and this information is captured within the attribute.
• Examples of attributes are “name”, “address” and “contact_number” that defines the attribute of customer.

Key fields

• A key field identifies the record uniquely in the database.
• It helps to retrieve, update and sort the record.
• For example, in a database, person name cannot act as key field, because there may be another person with same name. Hence instead of that field, social security number is taken as key field for searching the record and hence it is unique.

Explanation of Solution

Problems in a traditional file environment

The problems of traditional file environment include:

Data redundancy and inconsistency

• The copy of content in several fields leads to redundancy and hence duplication occurs.
• This is because the organization stores same content of data in different names independently.
• This wastes the resource for storage and hence leads to inconsistency.
• Hence this leads to confusion because different coding systems are represented for same attribute.

Program data dependence

• This represents the coupling of data in file with small programs to update and maintain files.
• If there are changes in the data, then the dependent file also need to be changed.
• That is if the original data file is changed, then the other files related to that original file also needs to be changed.

Lack of flexibility

• The traditional file creates scheduled reports after programming and it is very hard to create new reports.
• Ad-hoc report file is not able to create.
• This report file cannot be created because it is expensive and needs more time and programmers for creating the intermediate files.

Poor security

• Here the management has little control over company data.
• Hence there is no way to trace back the person who accessed or changed the data.
• Hence it provides poor security to the data.

Lack of data sharing and availability

• It is impossible to share the data.
• This is because data is scattered across several files and hence it cannot be collected from different parts.
• Hence it cannot be accessed in specific time.