Relational database revised

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 program
Used 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.

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

Relational database revised

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