CHAPTER 1: FUNDAMENTALS OF DATABASE MANAGEMENT SYSTEM, MUHAMMAD UKASYAH AL…
CHAPTER 1: FUNDAMENTALS OF DATABASE MANAGEMENT SYSTEM
1.2 UNDERSTAND DBMS
DEFINITION: A SOFTWARE SYSTEM WHICH ENABLES USER TO DEFINE,CREATE,ORGANIZE,UPDATE,MANAGE AND ADMINISTER DATABASES.
DBMS ALSO CONTROLS ACCESS TO DATA IN A DATABASE.
EXAMPLE : MS Acess, Oracle, MySQL,Filemaker,etc...
USERS OF DBMS
End user are the people who use the application programs to run the organization daily operations.
For example, sales clerks, supervisor, managers, and director are all classified as end users.
Application programmer is an individual who writes application programs in a user organization.
Database administrator manage the DBMS and ensure that the database is functioning properly.
PURPOSE OF DATABASE SYSTEM
Database system attempts to solve the difficulties in conventional file processing system.
Examples: - data redundancy and inconsistency
difficulties in accessing data
concurrent access anomalies
TRADITIONAL APPROACH TO INFORMATION PROCESSING
In traditional approach , information is stored in flat files which are maintained by the file system under the operating system control.
Application programs go through the file system in order to access these flat files.
DISADVANTAGES OF TRADITIONAL APPROACH TO INFORMATION PROCESSING
Data security: the data stored in the flat file can be easily accessible and hence it is not secure.
Data redundancy; in this storage model,the same information may get duplicated in two or more files. this may lead to higher storage and access cost. it also may lead to data inconsistency.
Data isolation; Data isolation means that all the related data is not available in one file.
Lack of flexibility; the traditional systems are able to retrieve information for predetermined requests for data.
Program /data dependence; In traditional file approach ,application programs are closely dependent on the files in which data is stored.
The Importance of having DBMS
integrity can be enforced
inconsistency can be avoided
standards can be enforced
restricting unauthorized access
providing backup and recovery
1.3 UNDERSTAND DATA MODEL
Data model is an integrated collection of concepts for describing and manipulating data, relationships between data and constraints on the data in the organization.
A model is a representation of real-world objects and events, and their association.
A data model represents the organization itself.
Evolution of Data Model:
1960s-1970s (File system)
1970s (Hierarchical and network)
Mid-1970s to present (Relational)
Mid-1980s to present (Object-oriented, Extended Relational)
Present to future (XML)
Object Based Data Model:
It is designed using the entities in the real world, attributes of each entity and their relationship.
ER Data Model
ER model is a graphical representation of real world objects with their attributes and relationship.
Record Based Logical Model:
Record based logical models are used in describing data at the logical and view levels.
The Network model represents data as record types and also represents a limited type of one to many relationship, called set type.
Relational data model
Data and relationships are represented by a collection of tables.
The Hierarchical model represents data as a hierarchical tree structures. Each hierarchy represents a number of related records.
THREE-SCHEMA ARCHITECTURE OF DBMS
ANSI-SPARC (American National Standard Institute – Standard Planning and Requirements Committee) proposed a 3 schema architecture.
The middle level between the external and the internal levels.
Represent what data & relationship between data. Represent a complete organizational environment.
Supports the external scheme where any data useful to users need to be stated in this level.
Lowest Level of ANSI/SPARC and closest to a DB.
Explain how data is stored in a database.
Covers physical implementation of the DB for optimum runtime and data structure/file organization used to store data in storage instrument.
User’s view of the DB where only a part of the database is suitable to the requirements of each user
Views of Users:
Some views only stored virtual data where the data can be produced only when needed.
The same data can be viewed and presented differently.
Accessibility to certain data, defined in specific views, is restricted to users.
The goal of the three-schema architecture is to separate the user applications and the physical database.
CLIENT-SERVER ARCHITECTURE OF DBMS
Has very high processing capabilities.
Its acts as a monitor to other clients computers connected to it in a local area network.
DBMS is located in a computer called server.
Capable of reducing cost because users are able to use personal computers or workstations as server and client.
Able to share resources such as scanner, printers etc.
Server computer is known as the ‘backend’ whereas the client computer acts as the ‘front-end’.
A server database is a computer program that provides database services to other computer programs or computers, as defined by the client–server model.
The term may also refer to a computer dedicated to running such a program.
BENEFITS OF USING SERVER DATABASE SOLUTION
Desktop databases offer simple, flexible solutions for data storage and retrieval.
They're often quite sufficient to meet uncomplicated database requirements for both small and large organizations.
BENEFITS OF USING DESKTOP DATABASE SOLUTION
Low Running Costs
Easy To Use
1.1 UNDERSTAND DATABASE
1)A collection of related data shared by various categories of users to fulfill the information needs and requirements of an organization.
2)A database application is a program application written in a specific programming language.
DATABASE IN EVERY DAY LIFE:
Databases are everywhere and have extensive effect in our life.
Online TV streaming
IMPORTANCE OF DATABASE TO EVERYDAY LIFE:
1)A database can be used at once is shared by many users.
2)Perform protection and data security.
3)Overcoming difficulties in accessing data.
4)Control of data redundancy.
5)Provision for multiple views of data.
6)Enforcement of integrity constraints
DATA DEVELOPMENT PROCESS:
1)Data modeling is the first step in the database development process.
It involves collecting and analyzing the data that a business needs to track, and then diagramming the organization of that data in an Entity Relationship Diagram.
2)Step two, the database design phase of the development process, translates the information modeled on the entity relationship diagram to a table instance chart.
The table instance chart lists the design specifications of the information and has the following components:
• Table name
• Column names
• Keys: a primary key (PK) & foreign key (FK)
• Nulls: indicates if a column must contain a value (mandatory)
Unique: indicates if the value contained in a column is unique within the table.
• Data type: identifies the definition and format of the data stored in each column.
3)Step three, database build.
Structured Query Language (SQL) commands are used to build the physical structure of the database.
SQL is also used to populate, access, and manipulate the data within the relational database.
The ability to share the same data resource with multiple applications or users.
PROPERTIES OF A DATABASE:
There are many possible choices that can be made during the design and many rules to guide this work.
When trying to decide if some choices are better than others, you need to consider the key desirable properties of a database.
Ensures that users can access the data they want. Note that this includes ad hoc queries, which would not be explicitly given as part of a statement of data requirements.
Ensures that data is both consistent (no contradictory data) and correct (no invalid data), and ensures that users trust the database.
Ensures that a database can evolve (without requiring excessive effort) to satisfy changing user requirements.
Ensures that users do not have unduly long response times when accessing data.
Usability (ease of use)
Ensures that data can be accessed and manipulated in ways which match user requirements.
USES OF DATABASE IN BUSINESS WORLD:
Databases are powerful organizational tools that help businesses quickly record, view and respond to important information. When used effectively,they can improve the efficiency and profitability of a business.
Example of database role in business world:
Customer relationship management: allows businesses to document every interaction with a current or potential customer, leading to more efficient marketing and sales departments.
keep track how much inventory is in a warehouse, in a storage room and on store shelves.
using a database to manage employee information can simplify scheduling and help prevent payroll errors.
reporting features of databases make them useful resources for analyzing data and predicting future trends.
MUHAMMAD UKASYAH AL JAUHARI
Abdul Hafiy Kamaluddin Bin Abdul Rani