Database Operations Flat-File and Relational Database

Source: Chapter 7, Tomorrow’s Technology & You (8th ed) by G Beekman & M Quinn

Objectives

So the students will be able to – Identify and discuss database

operations Understand and explain the various

special purpose databases Explain the difference between a flat-

file and relational database Explain the concept of one-to-one and

one-to-many relationships

Database Operations

Imports data from other sources - from word processors, spreadsheets, or other databases

Browsing records Database queries Query – an information request; can

be a search for a specific record or all records that match a set of criteria

Database Operations

Sorting Data – allows you to arrange record in alphabetic or numeric order based on values in one or more fields

Print reports, labels, and form letters

Display reports on screen or on printouts

Database Operations

Complex queries – can be done using SQL (Structured Query Language)SQL , a special query language

featured in most database programUsed to filter the records of a

database, capturing only those that meet the specific criteria

Use common English language and common logical operator OR and AND.

Database Operations

Use handout on – The Language of Database Queries

Example of SQL statements: Select Vehicle_ID, Vehicle_Type

FROM Rental_Vehicles WHERE Transport_Mode = ‘Land’ AND Rental_Price < 20.00

Special-Purpose Database Programs (SPDPs)

Preprogrammed for specific data storage & retrieval purposes

Users do not need to define file structures or design forms because these were taken care of by the software

Example of SPDPs

1. Directories – electronic phone

directory that pack millions of names & phone numbers onto a single CD-ROM or Web site

Electronic street atlas – uses information to provide location feedback for travelers & mobile workers from GPS feeds

Example of SPDPs

2. Geographic Information Systems (GIS) – simple mapping and tracking programs that combines tables of data from various sources Displays geographic and

demographic data on maps

Enable users to see data relationships that might be invisible in table form

Example of SPDPs

3.Personal Information Managers – can automate address / phone books, appointment calendars, to-do list, miscellaneous notes

Types of database programs

1. File managers – a program that enables users to work with one file at a time.

Example: FileMaker Pro

2. Database Management System (DBMS) - a program that manipulate data in a large collection of files (database), cross-referencing between file as necessary

Example: MS Access, Oracle

Type of Database structures

Flat-file database – a database in which all records are stored in one large table. For example, in a flat-file customer order, a customer’s address, phone number, & other important information will be entered over and over again every time a customer placed an order.

Characteristics of flat-file databases: It requires redundant data, which resulted

into files of large sizes. It is difficult to maintain because it

requires a large pool of human resources that equates to more salaries, office space and equipment.

Example: Flat-file database

Type of Database structures

Relational Database – a type of database which consists of more than one file or table that are linked to each other by a common data and in which changes in one file are reflected automatically in other related files.

The Relational Database Theory - solved the problem of redundant data (in a flat-file format).

Dr. E.F. Codd – introduced the relational database theory in his published paper entitled “A Relational Model of Data for Large Shared Data Banks” in 1970.

He introduced a set of rules that eliminate the need to store redundant data and formed the origin of relational database theory.

Example of a

Relational

database

Advantages of Relational databases

1. Eliminate redundant data reduces the number of times a data item is

entered therefore, minimizing data entry error. Each data item is stored only once, so if an error

is made, only one entry will be corrected.

Advantages of Relational databases

2. Reduce data inconsistencies Data consistency – means rules or procedures

followed in the entry and processing are one and the same for all users

3. Protect data integrity Data integrity – concerned with the correctness

of data; data free from errors