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INTRODUCTION TO OFFICE MANAGEMENT TOOL-II
Microsoft Access
3. Week-1
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Introduction to Database
Who need a Database?
Data vs Information
Data Processing and their Activities
Database Terminology
Keys Used in DBMS
Database Management System
Relational Database Management System
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4. Week-2
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Introduction to Database (Cont’d)
Types of Database
DBMS Applications
Database User’s
Components of DBMS
Database Models
Objectives of RDBMS
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5. Introduction
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Definition
The term database means different things to different people. However,
the following definitions are used in the literature:
A database is a collection of logically related data sets or files.
Each file may contain different types of information and are used for specific
purpose.
The files may be organized in different ways to meet different processing
and retrieval requirements of the users.
A Database is an organized collection of stored data. OR
Database is a structure collection of logically related data.
OR
An organized collection of information in computerized format.
or
A Computerized representation of any organizations flow of information and
storage of data.
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6. Introduction (Cont’d)
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Example
A bank may have separate files for the clients as follows:
Saving A/C, Automobile Loan, Personal Loan, Clients Information etc
The client database of bank will consist of the records from all of the above files.
The data of any client can be added, retrieved, or updated by using database
program.
The facilities of database are:
Adding new file to database
Inserting new data in existing files
Retrieving data from existing files
Updating data in existing files
Deleting data from existing files
Removing existing files from database
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7. Who Needs a Database?
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Anyone who uses information to market their business.
Anyone who uses information to provide goods or services to their customers.
Anyone who wants to save time and improve the efficiency of using their
business information.
Anyone who wants to be more organized about their business information.
Anyone who wants to use information about their business more consistently.
Anyone who wishes to present their business documents or output more
professionally.
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8. Introduction (Cont’d)
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Data (Cont’d)
The database is the collection of data about anything, Like cricket teams,
students and many more, anything about which you want to store data.
What we mean by data; simply the facts or figures.
Following table shows the things and the data that we may want to store
about them:
Cricket Country, name, date of birth, specialty, matches played, runs etc.
Player
Scholars Name, data of birth, age, country, field, books published etc.
Movies Name, director, language (Punjabi is default in case of Pakistan)
etc.
Food Name, ingredients, taste, preferred time, origin, etc.
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9. Introduction (Cont’d)
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Data (Cont’d)
Data is a collection of facts made up of text, numbers, figures, dates and
objects. An objects can be a person, event or anything about which data is
gathered.
Data is a valuable resource to any business.
Data can be used by the managers to perform effective and successful
operations of management.
It provide a view of past activities related to the rise and fall of an
organization.
It also enable the user to make better decision for future.
Date is very useful for generating reports and graphs.
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10. Introduction (Cont’d)
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Data (Cont’d)
Example
Data can be names, addresses, phone numbers, dates etc.
Mr. Khan 35000 7/18/86
Data can be processed to create useful information. Information is the
meaning given to data in the way it is interpreted:
Mr. Khan is a sales person whose annual salary is $35,000 and whose hire
date is July 18, 1986.
The manipulated and processed form of data is called information.
It is more meaningful than data.
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11. Introduction (Cont’d)
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Data vs Information
Data is unprocessed raw facts about a particular entity while Information is the
processed form of data.
Data is used as input in the computer while Information is the output of computer.
Data in normally huge in the volume while Information is normally short in the
volume.
Data is the asset of organization and is not available to people for sale while
Information is normally available to people for sale.
Data is difficult or impossible to reproduce while Information is easier to
reproduce if lost.
Data is used rarely while Information is used frequently.
Data is an independent entity while information depends on data.
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13. Data Processing and Activities
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The process of manipulating data to achieve the required objectives and
results is called Data Processing.
Software used to process raw data and converts raw data into meaningful
information.
Series of actions or operations are performed on data to get required
output or results.
Activities on Data Processing
Data Capturing
Data Manipulation
Managing output results
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14. Data Processing and Activities (Cont’d)
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Data Capturing
Process of recording the data in some form is called Data Capturing.
Data may recorded from source documents. Or
Data can also be given directly to the computer through input devices.
Data Manipulation
Process of applying different operations on data is called Data manipulation.
The following operation can be performed on data:
Classifying
Process of organizing data into classes or groups is called classifying.
Example: Data in college can be classified in two groups: Student & Teacher
Calculation
Process of applying arithmetic operations on data is called Calculation.
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15. Data Processing and Activities (Cont’d)
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Sorting
Process of arranging data in logical sequence is called sorting
Summarizing
Process of reducing a large amount of data in a more concise and usable form is
called summarizing.
Managing output results
The following activities can be performed on data after the data has been captured
and manipulated.
Storage
Process of retaining data for future use is called data storage.
Different storage medium used to store data.
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16. Data Processing and Activities (Cont’d)
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Retrieval
Process of accessing or fetching the store data is called data retrieval.
Data can be retrieved when required.
Communication
Process of transferring data from source to destination for further processing is
called communication.
Reproduction
Process of copying or duplicating data is called reproduction of data.
Data can be reproduced if different users need data at different locations.
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17. Database Terminology
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Database File
The main file that include the entire database and that is saved to your hard-drive or
floppy disk. For example StudentDatabase.mdb in access 2003 and .accdb in access
2007 & 2010
Also called Master files or Latest updated files
These files are updated when any change in their are required.
Transaction File
It is used to store input data before processing.
It may be temporary file or may exist until the master file is updated.
It may also be used to maintain a permanent record of the data about a transaction.
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18. Database Terminology (Cont’d)
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Backup File
It is used to take backup of important data.
It is permanent file.
It is used to store an additional copy of data.
Data can be recovered from this file if the original file is lost or damaged.
Backup files are mostly created by using specific software utilities.
Entity
Real world things (entities) you need to store information about.
For example Employees, Products, Customers, Orders.
Entities are represented by tables in the database
Entities are represented by rectangles
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19. Database Terminology (Cont’d)
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Table
A two dimensional array of data that contains descriptive information about
an entity is known as table or relation.
A table is a collection of data about a specific topic, such as students or
contacts, Customers, Orders, or products.
Field
Facts (attributes) you need to know about each entity, e.g. an Employee’s
date of birth, salary.
Attributes are represented by fields in the tables
A field is a single characteristic of a person, place, object, event or idea.
Attributes are represented by oval.
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20. Database Terminology (Cont’d)
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Record
A set of related field values. e.g. An employee record includes a set of
fields about the employee such as Employee no, name etc.
Degree
Degree is the number of attributes in a relation.
Cardinality
Cardinality is the number of tuples in a relation.
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21. Example
Relationship
A logical connection between different entities is called relationship
Fields
Records
Student ID Student Name Phone Department
101 Khan 392-3900 Pharmacy
102 Jawad 392-5555 Statistics
103 Imran 846-5656 Economics
Course Code Course Name Student ID
1001 Botany 101
1002 SPSS 102
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22. Primary Key & Foreign Key
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Primary Key
To ensure that each record is unique in each table, we can set one field to
be a Primary Key field.
A Primary Key is a field that will contain no duplicates and no blank
values. Or
A Primary key is a field, or a collection of fields, whose values uniquely
identify each record
Foreign Key
When the primary key is included in a second table, it’s called as a Foreign
key
Foreign Keys link to data in other tables
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23. Candidate/Alternate, Composite & Secondary Key
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Candidate/Alternate Key
Field or combination of fields that are not used as a primary key.
Users can also access data by using an alternate key.
e.g.
If student relation contain a Roll No, it can be used as primary key because one Roll
No can be assigned to only one student.
Suppose the relation contains another field Registration No that has been used as
primary key. In this situation, Roll No becomes an alternate key.
Composite Key
Primary key that consist of two or more attributes
e.g.
Relation uses two fields Registration No and Subject to identify each tuple, then it is
called Composite key.
Secondary Key
A field or combination of fields that is basis for retrieval is known as secondary key.
Secondary is a non-unique field. One secondary key may refers to many records.
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27. Database Management System
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A DBMS is a software tool that allows multiple users to store, access, and
process data into useful information.
Used for Organizing, Storing, Maintaining, Retrieving, and Sorting data.
A RDBMS is a collection of tables that are related to one another based
on a common field.
A relational database uses multiple tables
Example: Microsoft Access, dBASE, FOXPRO, Oracle.
To manage databases, companies purchase programs called RDBMS
Student Information System
Inventory System
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28. Relational Database Management System (RDBMS)
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Relationships between the entities in the database; i.e. what attributes do
they have in common.
Relationships are formed in the database between entities that have
common attributes. They have common fields in the related tables.
For example, customer ‘Hassan’ can place an order for product ‘Laptop’.
So the Orders table has relationships with Customers table & Products
table
DON’T DUPLICATE DATA
That is, once relationships are created, tables can “talk” to each other. We
can link (relate) the tables to find:
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30. DBMS Applications (Cont’d)
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The purpose of a relational database management system is to transform
Data Information Knowledge Action
Data driven decision making
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31. Types of Database
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Two types of databases are Centralized & Distributed Database
Centralized Database
A logically interrelated collection of shared data, physically located on a
central computer and the user access this data base through their
terminals.
All the processing is performed on that central computer.
It provide greater control over accessing and updating data than
distributed databases, however,
Centralized databases are more vulnerable to failure since they depend
on resources at a central location.
Examples
Personal Computer Databases- those used in small businesses (Accounting,
Inventory)
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32. Types of Database (Cont’d)
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Central Computer Databases- Usually involve very large, integrated
databases accessible to a large number of users (Airline reservation system,
Financial Institutions, etc.)
Client/Server Database- Designed for distribution of work on a computer
network in which many clients share services of a single server.
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33. Types of Database (Cont’d)
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Distributed Database
A logically interrelated collection of shared data, physically distributed
over a computer network.
A distributed database (DDB) is a collection of multiple, logically
interrelated databases distributed over a computer network.
The database must have a single logical data model.
e.g. Banking and insurance applications
DDB increase reliability and availability
When centralized database fails, the database is unavailable to all users. A
distributed system will continue to function at some reduced level even when a
component fails.
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35. Database User
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Users of Database Systems:
Application Programmers
End Users
Naïve User
Sophisticated User
Database Administrator
Application programmers:
who create different types of database application programs
Application programmers design the application according to the needs
Application programmers are skilled people who have clear idea of the
structure of the database and know clearly about the needs of the organizations.
End Users:
Group of users contains the people who use the database application
programs developed by the Application programmers. This category further
contains three types of users AbduSalam
36. Database User (Cont’d)
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This category further contains three types of users
Naïve Users
Sophisticated Users
Database Administrator
Naïve Users
Simply use the application database programs created by the programmers.
Has no interaction with other parts of there database and only use the programs
meant for them.
They have not to worry about the further working of the database.
Sophisticated Users:
Have some additional rights over the Naïve users, which means that they can
access the data stored in the database any of their desired way.
Can access data using the application programs as well as other ways of
accessing data.
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37. Database User (Cont’d)
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Database Administrators (DBA):
The most technical class of db users.
Have the knowledge of how to design and manage the database use as well as
to manage the data in the database.
DBA is a very responsible position in an organization for development of any
database system.
Responsible for design, proper working, implementation, operation of the
database and RDBMS, has the responsibility of making proper database
backups and make necessary actions for recovering the database in case of a
database crash.
To fulfill the requirements of a DBA position a DBA needs vast experience
and very elegant technical skills.
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38. Database User (Cont’d)
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Database Administrator takes over the charge and performs specific DBA related
activities including:
Installation of software
Database maintenance
Database Backup
Grant of rights to database users
Responsible for grant of access rights to the database users.
Granting and revoking (taking back) the rights
Monitoring of Running Jobs
When a new database is created it takes a limited space but as a result of
daily activity the database acquires more data and grows in size very
rapidly.
The DBA has to monitor the disk space usage and statistics to ensure that no
data over flow occurs at any stage.
Managing Print jobs
Restoring the system AbduSalam
39. Components of Database System
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The four major components of Database System are:
Data
Data is the most important component of database system.
Data covers the collection of facts stored in the database.
Main purpose of database system to store, maintain and process data for the user.
Hardware
Physical components of a computer system are known as hardware.
Hardware are used to perform different tasks as input, output, storage, and
processing.
Software
Collection of programs used by computer within a database system.
Most important software is DBMS itself.
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40. Components of Database System (Cont’d)
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Three types of software to enable the database system function fully.
Operating System software
It manages all the hardware components and enable other software to run on the
computer.
RDBMS software
It manages the database in the database system
Application Programs and Utilities
Used to access and manipulate the data stored in the database
Personnel
People related to database system are called Personnel
e.g. DBA, Programmer, & End User
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41. Database Models
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Set of rules and standards that define how the database organizes data is
called Database Model.
Three types of logical database models
Hierarchical Model
It arranges records in hierarchy like an organizational chart.
Each record type in this model is called a node or segment.
Node on the chart represents a particular entity.
Each node is a subordinate of the node that is the next highest level.
This kind of structure is often called inverted tree.
The top-most node is called Root.
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43. Database Models (Cont’d)
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Network Model
Each record can have multiple parents
Network model is similar to hierarchical model.
Major difference is that the subordinate entity may participate in as many subordinate
relationships as required.
Subordinating entities are represented by arrows in the network model.
Require more complex program to represent a database. It also provide more
flexibility than hierarchical model.
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45. Database Models (Cont’d)
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Relation Model
Most commonly used database model and more flexible than others
Consists of simple relations and these relation represent a particular entity.
Relation are used to hold information about the entity to be represented in the
database.
Relations are also called Tables
Tables are a series of row/column intersections, Tables related by sharing common
entity characteristic(s)
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47. Database Models (Cont’d)
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Represented in an entity relationship diagram (ERD)
Based on entities, attributes, and relationships
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48. RDBMS Objectives
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RDBMS have some important objectives:
Database Security
Protection from malicious attempts to steal or modify data.
Database security means to protect the data from unauthorized (access) users,
which can modify, update, destroy or delete the data is known as Database
security.
Thus data base is always under a responsible person called DBA.
Authentication and authorization mechanisms to allow specific users access only to
required data.
Share ability
An ability to share data resources
Share ability means that the actual data must be shared among different people
and different processes at the same time.
This capability allows user to store data at a central place.
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49. DBMS Objectives (Cont’d)
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Availability
It means that the users must be able to access data easily.
The data should be available when and where it is required.
Integrity
Protecting the existing database, maintaining the quality of database and
ensuring the privacy of database.
The Integrity of a DB is concerned with its consistency, correctness, validity and
accuracy.
Database integrity refers to the validity and consistency of stored data.
Integrity is usually expressed in terms of constraints, which are consistency rules
that database is not permitted to violate.
Enforcing integrity constraints generally requires access to a large amount of
data that defines the constraints but which is not involved in the actual update
operation itself.
In a distributed DBMS, the communication and processing costs that are required
to enforce integrity constraints may be prohibitive.
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50. Types of Integrity
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Relational Integrity
CREATE Table Student
The primary key can neither be null nor duplicate.
(Std-ID INTEGER NOT NULL)
Referential Integrity
Thus referential integrity means that, if the foreign key contains a value, that
value must refer to an existing, valid row in the parent table.
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51. 51
Think about the data that you may want to store about
different things around you
List the changes that may arise during the working of any
system,
lets say
Railway Reservation System
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A database is a shared collection of logically related data, designed to meet the information needs of multiple users in an organization.
Data that describe the properties and context of user data.
A relational database is a collection of tables from which data can be accessed in many different ways without having to reorganize the database tables.
A relational database is a collection of tables from which data can be accessed in many different ways without having to reorganize the database tables.
A relational database is a collection of tables from which data can be accessed in many different ways without having to reorganize the database tables.
A relational database is a collection of tables from which data can be accessed in many different ways without having to reorganize the database tables.
Collection of logical constructs used to represent data structure and relationships within the database
Perceived by user as a collection of tables for data storage, Tables are a series of row/column intersections, Tables related by sharing common entity characteristic(s)
Collection of logical constructs used to represent data structure and relationships within the database
Think about the data that you may want to store about different things around you List the changes that may arise during the working of any system, lets say Railway Reservation System
Think about the data that you may want to store about different things around you List the changes that may arise during the working of any system, lets say Railway Reservation System
