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CHAPTER 1: FUNDAMENTALS OF DBMS, Uses of databases in bussiness world,…
CHAPTER 1: FUNDAMENTALS OF DBMS
1.2 Understand DBMS
DISADVANTAGES OF TRADITIONAL APPROACH TO INFORMATION PROCESSING
(Siti Sarah)
PROGRAM/DATA DEPENDENCE
-The close relationship between data stored in files and the software programs that update and maintain those files.
-Any change in data organization or format requires a change in all programs associated with those files
-each of the application programs that a programmer writes or maintains,the programmer must be concerned with data management,
-no centralized execution of data management functions.
-Data managementis scattered among all the application programs
(Nur Arni Syamira)
DATA ISOLATION
-Means that all the related data is not available in one file
-A property that determines when and how changes made by one operation become visible to other concurrent users and systems
(Nur Arni Syamira)
LACK OF FLEXIBILITY
-The traditional system can deliver routine scheduled reports after extensive programming efforts but it can not deliver ad hoc reports or respond to unanticipated
information requirements in a timely fashion.
( Siti Zubaidah )
Data Security
the data stored in the flat files can be easily accessible and not secure
lack of security and limited data sharing are closely related.
sharing data among multiple geographically dispersed users introduces a lot of security risks.
ex: in terms of spreadsheet data, while many spreadsheet programs provide basic security options, they are not always used, and even when they are used, they are not enough for robust data sharing among users.
in terms of the creation of data management and reporting programs, security and data-sharing features are difficult to program so they are normally omitted in a file system environment
ex: features include effective password protection, the ability to lock out parts of files or parts of the system itself, and other measures designed to safeguard data confidentiality. Even when an attempt is made to improve system and data security, the security devices tend to be limited in scope and effectiveness
( Siti Zubaidah )
Data Redundancy
exists when the same data are stored at different places - the file system’s structure makes it difficult to combine data from multiple sources
since each application has its own data file, the same data may have to be recorded and stored in many files
ex: personal file and payroll file, both contain data on employee name, designation etc. The result is unnecessary duplicate or redundant data items.This redundancy requires additional or higher storage space, costs extra time and money, and requires additional efforts to keep all files upto-date
(Jocelyn)
Concurrent access anomalies
Many traditional systems allow multiple users to access and update the same piece of data simultaneously
However this concurrent updates may result in inconsistent data.
To guard against this possibility, the system must maintain some form of supervision.
But supervision is difficult because data may be accessed by many different application programs and these application programs may not have been coordinated previously.
1.2 UNDERSTAND DATABESE MANAGEMENT SYSTEM (DBMS) BY PAULUS AND ZECH (SLIDE 22-25)
DATABESE MANAGEMENT SYSTEM
(DBMS) (PAULUS)
Definition: A software system which enables user to define, create , organize, update , manage and administer databeses.
DBMS also controls access to data in a databese .
Example : MS Access , Oracle, MySQL, Filemaker, Microsoft SQL server , etc....
THE DATABESE SYSTEM ENVIRONMENT (PAULUS)
For clear picture , can refer to the notes chapter 1 . subtopic 1.2 slide 23
on cidos.
1.2 UNDERSTAND DATABESE MANAGEMENT SYSTEM (DBMS)
(SLIDE 26-28) BY ANDRIANA AND RACHEL
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
Data isolation
Integrity problems
Atomicity problems
Concurrent access anomalies
Security problems
Traditional approach to information processing
(Rachel)
In traditional approach, information is stored in flat files which are maintained by the file system under the operating system’s control
Application programs go through the file system in order to access these flat files
1.2 UNDERSTAND DATABASE MANAGEMENT SYSTEM (DBMS) BY MARK & NATALIE (SLIDE 29,30)
Traditional approach to information processing (cont.)
by Natalie
How data is store in flat files?
Data is stored in flat files as records
Records consist of various fields which are delimited by a
space
comma
pipe
any special character etc.
End of records and end of files will be marked using any predetermined character set or special characters in order to identify them
Traditional approach to information processing (cont.)
ZECHARIAH (05DDT20F2047)
User of DBMS
End User
people who use the application programs to run the organization’s daily operations.
example :
sales clerks
supervisors
managers
Application programmer
individual who writes application programs in a user organization.
Database administrator
a person/team who defines the schema and also controls the 3 levels of database.
THE IMPORTANCE OF HAVING DBMS
(CELIA)
1.CONTROLLING REDUNDANCY
-each application has its own private files, which cannot be shared between multiple applications.
-it can often lead to considerable redundancy in the stored data, which results in wastage of storage space. By having centralized database most of this can be avoided
2.INTEGRITY CAN BE ENFORCED
-data in database is always accurate, such that incorrect information cannot be stored in database.
-In order to maintain the integrity of data, some integrity constraints are enforced on the database.
3.INCONSISTENCY CAN BE AVOIDED
-When the same data is duplicated and changes are made at one site, which is not propagated to the other site, it gives rise to inconsistency and the two entries regarding the same data will not agree.
-At such times the data is said to be inconsistent. -So, if the redundancy is removed chances of having inconsistent data is also removed.
6.RESTRICTING UNAUTHORIZED
-When multiple users share a database, it is likely that some users will not be authorized to access all information in the database.
-In addition, some users may be permitted only to retrieve data, whereas other are allowed both to retrieve and to update. Hence, the type of access operation retrieval or update must also be controlled.
-provide a security and authorization subsystem, which the DBA uses to create accounts and to specify account restrictions. The DBMS should then enforce these restrictions automatically.
7.PROVIDING BACKUP AND RECOVERY
-provide facilities for recovering from hardware or software failures.
-The backup and recovery subsystem of the DBMS is responsible for recovery.
-For example, if the computer system fails in the middle of a complex update program, the recovery subsystem is responsible for making sure that the .database is restored to the state it was in before the program started executing.
4.DATA CAN BE SHARED
-The ability to share the same data resource with multiple applications or users
-implies that the data are stored in one or more servers in the network and that there is some software locking mechanism that prevents the same set of data from being changed by two people at the same time.
5.STANDARDS CAN BE ENFORCED
-can be enforced easily may be at Company level, Department level, National level or International level.
-The standardized data is very helpful during migration or interchanging of data.
The file system is an independent system so standard cannot be easily enforced on multiple independent applications.
1.1 Understand Database
User Database in business wolrd
Analyse
reporting features make useful resources for analyzing data and can predict what will occur in future
Personal Database
can manage office information and easily scheduling and guide to increase major error in office data system
Inventory Tracking
can route how much items is in office,storage shelves or restroom
Hafiq Rashdan bin Rashidi(05DDT20F2031)
Database Development Process
First step is data modelling
Collect and analyzing data that a business need to track it
can diagram the organization of data in an Entity Relationship Diagram
Database in Every Day Life
Databases are everywhere and have extensive effect in our life
Example:
E-commerce
Social media
Social gaming
Finances
Online TV streaming
Personal Cloud Storage
Sports
How Database In Every Day Life Ussd
Online TV streaming
Any online streaming service, such as Hulu or Netflix, uses databases to generate a list of TV shows and movies to watch. The database tracks an individual’s show preferences, and provide a list of recommended viewing.
Social Gaming
Gaming done across social networks is extremely data intensive. Gathering individual player information from around the globe and serving it to players on demand requires a high availability database software.
Finances
From the stock market to your local bank, databases are abundant across the financial world. Tracking the vast amount of information behind the world’s daily transactions requires extremely powerful databases. This includes financial models that analyze that data to predict future activity.
E-Commerce
The eCommerce store owner can then recommend other potential products to customers using platforms such as WooCommerce.This data is stored in highly secure databases, protected by the standards set through PCI Compliance.
Sports
Fan participation in national sports doesn’t just utilize the power of the database, it depends upon it. From fantasy football leagues to March Madness brackets, they all depend on huge databases full of player statistics. This includes game performances, injury reports, and more, all calculating the odds of a win on a weekly basis.
Social media
Every social media platform stores reams of user information in databases used to recommend friends, businesses, products, and topics to the end user. This cross-referencing of data is immensely complex and uses highly reliable and capable database software. For example, MySQL is used in Facebook data centers.
Personal Cloud Storage
If you save photos or documents to your smartphone or tablet, it’s likely your data is stored in “the cloud,” a large, central storage environment with a small portion dedicated just to you.
Syncing this data across your devices requires powerful databases able to call up your data at a moment’s notice, wherever you are.
Muhammad Irfan
Importance of database to everyday life
They communicate information related to our sales transactions
Databases allow for data to be stored quickly and easily and are used in many aspects of our daily life
App or device such a MyFitness works as tracks our daily activities like how how many calories have burned .
At hospital . patient can make appointment using websites and doctor can browse information about their patients
Database also for tracking and maintaning our finances
Database also can keep our record of music or book collections
Wan shukury
Data Sharing concept in database
The data are stored in one or more servers in the network
Examples of data sharing :
The data contains the locations of endangered/threatened species or valuable artifacts and will only be shared with trusted parties who agree to the reuse criteria.
Data sharing is a primary feature of a database management system (DBMS).
ZULHELMI
Database
What is database
An organized collection of structured information, or data, typically stored electronically in a computer system
Controlled by a database management system (DBMS)
DATABASE DEVELOPMENT PROCESS
(Evenilson, Rio and Wilson)
STEP 1 : :check:
Data modeling is the first step
collecting and analyzing the data that a business needs to track, and then diagramming the organization of that data in an Entity Relationship Diagram.
Evenilson
STEP 2 :check:
the database design phase of the development pr ocess, 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
:star: KEY
:check:(PK) PRIMARY KEY
Nulls: indicates if a column must contain a value (mandatory)
Unique: indicates if the value contained in a column is unique within the table
:check:(FK) FOREIGN KEY
:star:Column names
:star:Data type: identifies the definition and format of the data stored in each column
:star:Table name
Wilson
STEP 3 :keyboard:
DATA BASE BUILD
:check:
:star:
Structured Query Language (SQL) commands are used to build the physical structure of the database
:star:
Example
: Create table departments :check:
:recycle:
(deptno NUMBERS(5) CONSTANT depts_deptno_PK PROMARY KEY,
:recycle:
name VARCHAR2(25) CONSTANT depts_name_NN NOT NULL
:recycle: l
oc VARCHAR2(30) CONSTANT depts_loc_NN NOT NULL);
:star:
SQL is also used to populate, access, and manipulate the data within the relational database
:star:
EXAMPLE
: DATABASE BUILD :check:
:cyclone: SELECT fname,lname,deptno
1 more item...
:cyclone: UPDATE departmets
1 more item...
:cyclone: INSER INTO departments
1 more item...
Rio
Properties Of A Database
(Davidson, Arthur, Clerance Walter)
Many possible choices that can be made during the design and many rules to guide this work.
:star:
Usability :star:
(Ease of Use)
Ensures that data can be accessed and manipulated in ways which match user requirements.
:star:
Efficiency
:star:
Ensures that users do not have unduly long response times when accessing data.
:star:
Flexibility
:star:
Ensures that a database can evolve (without requiring excessive effort) to satisfy changing user requirements.
:star:
Integrity
:star:
Ensures that data is both consistent (no contradictory data) and correct (no invalid data), and ensures that users trust the database.
:star:
Completeness
:star:
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
When trying to decide if some choices are better than others, you need to consider the key desirable properties of a database.
Extra Properties of A Database:
ACID
(
https://www.chegg.com/homework-help/definitions/properties-of-a-database-3
)
Atomicity
Atomicity in database ensures that the transactions are indivisible and irreducible where transactions either commit or abort.
If a part of transaction fails then entire transaction fails.
Consistency
Any change in the values of a database at particular instance are consistent with changes to other values. Consistency on any transaction acts as a predicate for the data which serves as:
Precondition
Postcondition
Transformation condition
Isolation
Transaction in database ensures that the working transaction will not be changed or affected by any other transaction. In other words, modifications or updates made on one transaction is not viewed or changed by any other transaction.
Isolation also ensures the effect of database is same when
transactions are executed serially
or
executed in an interleaved fashion
.
Durability
Durability of the databases states that “once transaction has been committed, should remain in the same status” even in the case of failures such as:
Power loss
Database crash
1.3 Understand Data Model
nur athirah binti affandy (05DDT20F2023)
DATA MODEL DEFINITION
integrated collection of concepts for describing and manipulating data, relationships between data and constraints on the data in the organization.
A database model is a type of data model that determines the logical structure of a database. It fundamentally determines in which manner data can be stored, organized and manipulated
EVOLUTION OF DATA MODEL
OBJECT BASED DATA MODEL
It is created utilising real-world entities, as well as their properties and relationships.
example :entity-relationship (ER) data model.
DAVELYN (05DDT20F2059)
BENEFITS OF USING SERVER DATABASE SOLUTION
Scalability
Because SQL databases are served through a service and are based on SQL syntax they are in fact much more scalable meaning that they are used by some of the largest database driven websites on the internet.
Having scalability allows you to grow your website without having to worry about the database crashing or not being accessible because there are simply too many people using it at one time.
Wider integration
SQL database systems can normally be used by many different scripting languages.
For example ASP.NET and classic ASP have the ability to be used with both Microsoft SQL Server database servers and MySQL based database servers which provides webmasters with a good choice of database server that they can use when it comes to making their website database driven.
FAIRUL ISZWAN (05DDT20F2055)
BENEFITS OF USING SERVER DATABASE SOLUTION
Desktop management
Like desktop database systems, SQL database servers can also be managed from the desktop using external tools which will connect to your SQL database server so that you are able to manage the different databases that users have created on your server.
Although you can also make use of web admin panels and other forms of SQL database management that are now available to you.
SUMMARY
What you have learned in Chapter 1:
Database definition
Evolution of database
Importance of database
3 steps of database development and design
Properties of database
1 more item...
Importance of DBMS
Centralized and distributed database
Data model definition
Object based data model: ER
Record based data model: hierarchical, network and relational data model
1 more item...
Muhammad Thaqif Zakirin Bin Hassan(05DDT20F2072)
Object Base Data Model:ER model is a graphical representation of real world objects with their attributes and relationship
Record base logical
4.The three example of record based data models are: hierarchical model, network model and relational model.
3.Record-based models get their name from the fact that the database is organised into fixed-format records of various sorts. Each record type has a specific amount of fields, or attributes, and each field has a specific length.
2.They are used to specify the general logical structure of the database and provide a higher-level description of the implementation, as opposed to object-based data models.
1.At the logical and view levels, record-based logical models are used to describe data.
Record Based Logical model: Hierarchical model
Data is represented in the Hierarchical model as hierarchical tree structures. Each hierarchy depicts a group of records that are connected to one another.
Heskey anak Harrsion Juna (05DDT20F2005)
Three-schema Architecture Of DBMS
External Level
User’s view of the DB where only a part of the database is suitable to the requirements of each user
Accessibility to certain data, defined in specific views, is restricted to users.
The same data can be viewed and presented differently.
Some views only stored virtual data where the data can be produced only when needed.
JEFFERSON LUKE (05DDT20F2053)
CLIENT-SERVER ARCHITECTURE OF DBMS
Server computer is known as the ‘backend’ whereas the client computer acts as the ‘front-end’.
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.
Typical Client-Service Arrangements of Database and Software
DESKTOP DATABASE
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.
LUQMANUL HAKIM BIN ZAINORIN
DESKTOP DATABASE
Desktop products include:
MicrosoftAccess
ParaDox
FileMakerPro
ExBase derivatives such as FoxPro and ClipperLanguage
Lotus
BENEFITS OF USING DESKTOP DATABASE SOLUTION
Easy Management
Programs such as Microsoft Access are desktop based.
When you need to edit something, all you have to do is download the necessary file from your web space and from there you can use the program to edit and modify your database.
Once you have carried out all your modifications you can easily upload your modified database to your web space where all changes will be immediate
Low Running Costs
To begin with all you have to do is purchase the necessary desktop database program so that you can create and manage your databases.
After that you can normally freely use your chosen application to create and modify as many databases as you wish, but it must be noted that you can only use the intended program to modify your database unless you build your own web-based interface
AUSTIN LARRY SAIT ANAK GERAMAN(05DDT20F2046)
Three-Schema Architerature Of DBMS
Internal Level
Lowest level of ANSI / SPARC and closet to a DB.
Internal schema which describe the physical storage structure of the database.
It is used to define that how the data will be stored in a block.
The physical level is to describe complex low-level data structures in detail.
[IFWAT (05DDT20F2061]
BENEFITS OF USING DESKTOP DATABASE SOLUTION
:
Easy to use
Since desktop database systems are desktop based, no knowledge is necessarily needed to be able to manage such databases since the programs themselves are normally very intuitive and easy to learn
.
Since the databases themselves aren’t SQL based there is no need to have any prior knowledge of SQL
SERVER DATABASE
A computer program that provides database services to other computer programs or computers, as defined by the client–server model, may also refer to a computer dedicated to running such a program.
Some examples of Database servers are Oracle, DB2, and SQL Server.
Every server uses its own query logic and structure
The SQL query language is more or less the same in all the database servers
NURUL IFFAH UJAN (05DDT20F2050)
Record Based Logical model: Network model
represents data as record types and also represents a limited type of one to many relationship
Record Based Logical model: Relational data model
represented by a collection of tables
Each table has a number of columns with unique names, e.g. customer, account.
THREE-SCHEMA ARCHITECTURE OF DBMS
ANSI-SPARC
(American National Standard Institute – Standard Planning and Requirements Committee) proposed a 3 schema architecture
goal of the three-schema architecture
separate the user applications and the physical database
Uses of databases in bussiness world
Databases are powerful organization tools that help bussiness quickly record,view and respond to important information
When used effectively,they can improve the efficiency and profitability of a bussiness.
Example in business world:
Customer realtionship management allows businesses to document every interaction with a current or potential customer, leading to more efficient marketing and sales department
(nurishya)
Database Architecture
( 2 generic database architecture)
CENTRALIZED DATABASE
1)Is stored in a single place such as a mainframe computer or a server .
2) Users in remote locations access the data through the (WAN) using the application programs provided to access the data
DISTRIBUTED DATABASE
1) The data is stored in storage devices that are located in different physical locations
2)not attached to a common CPU but the database is controlled by a central DBMS
3)Users access the data in a distributed database by accessing the WAN
4) Uses the replication and duplication processes to keep database up to date .
5)The replication process identifies changes in the distributed database and applies those changes to make sure that all the distributed databases look the same.
Mohd Haziq Iman
Ridzuwan
Andriana
Andriana
MARK
MARK
