Database management system

Sayed Ahmed
Computer Engineering, BUET, Bangladesh
MSc, Computer Science, U of Manitoba, Canada
Owner/President/Architect/Developer
Justetc (Just et cetera) Technologies
http://www.justetc.net
http://sayed.justetc.net
sayed@justetc.net

Syllabus and Learning
Objectives

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Learning Objectives
 Concept of Database and Database
Management System
 Activities of a Database Management
System
 What is a Relational Database
Management System
 Features of Relational Database
Management System

Learning Objectives
 Create database
 Concept and explain the importance of
Data Security
 Data Encryption
 Importance
 Methods
 Querying Database: Query Language:
SQL
 Uses of Databases

What is a Database?
 Database means
 Data storage
 A good/organized/efficient way of storing data
 You can store all the information of a library into
a database
 How are information stored in computers?
 In files; you know it when you learn to use
computers
 Files are stored in computer hard drives, USB
sticks, memory cards

What is a Database
 Is there anything different of storing data
by a database
 Not much, databases also store data in files
 However, a database stores data in files in a
very organized way so that it becomes easir
to
○ Insert new data into the file/files
○ Easier to search, sort, and retrieve data from
those files

What is a Database
 Let’s see, you can store all information
of a bank in a computer file
 All bank account information
 All employee information
 All account holder information
 All branch and department information
 You can keep them in a single file; but can
be very difficult to find something useful fast;
also inserting data and managing the file
can be difficult

What is a Database
 Now you can store all data in multiple files; just
divide the original file into multiple files;
○ Still if you do not organize the files or the data in them,
it can be very difficult to work with them
○ In a database, information are kept eventually in
computer files
 However, a database will use a good strategy on how to store
those data into files
 Databases will store the data in many files
 Will store in such a way so that it becomes easier to work with
the files and the data
 In real life, we have systems and software that knows about
the strategy and helps to deal with those files and data for
efficient storing, searching, retrieving, doing operations on the
data and store the result in the same databse
- We call such systems and software to the Database
Management System

What is a database
 One strategy
 Keep one type of data into one file
○ Such as in one file, store all bank account holders
personal information
○ In another file, keep the details of all the bank accounts
○ In another file, keep the association between these
accounts and account holders
○ If the number of records in a file is two many, divide the
files into multiple files but keeping the same type of
information; find a way to keep track which files are
related
○ Create some other files to keep track of which files
store what
○ Create some other files that can store the
location/address/position of a particular data in other
files [index file]

What is a Database Management
System
 If we have software that implements the
strategy described above, can be called a
DBMS
 When we feed data into it, if it can store the
data using that strategy and provides ways
to manipulate the data in an efficient way
 Then we can call this software to be a DBMS
 DBMSes usually display data in tabular format
(row/column - format)

Database and Database Management
Systems
 From Wikipedia, the free encyclopedia
 A database
 is an organized collection of data. The data are typically organized to
model relevant aspects of reality in a way that supports processes
requiring this information. For example, modeling the availability of
rooms in hotels in a way that supports finding a hotel with vacancies
 Database management systems (DBMSs)
 are specially designed applications that interact with the user, other
applications, and the database itself to capture and analyze data. A
general-purpose database management system (DBMS) is a software
system designed to allow the definition, creation, querying, update, and
administration of databases. Well-known DBMSs include MySQL,
PostgreSQL, SQLite, Microsoft SQL Server, Microsoft Access, Oracle,
SAP, dBASE, FoxPro, IBM DB2, LibreOffice Base and FileMaker Pro. A
database is not generally portable across different DBMS, but different
DBMSs can inter-operate by using standards such as SQL and ODBC or
JDBC to allow a single application to work with more than one database.

Activities provided by a
DBMS
 DBMS can create a database
 i.e. Create the initial structure of the database
 Allocate space and saves the database in the hard
drive
 Control who can use a database
 Take data from user and record and store it
somehow
 Organize data
 In meta files or in actual data files
 Provide means to search and display the data
 Provide security of the data
 Maintain the integrity of the data

Advantages of a DBMS
 Improved availability
 To different users, efficient retrieval of data
 Minimized redundancy
 Data are organized in a way so that the same
data are not stored in multiple places/files
 Accuracy
 Can keep data consistent as 1. redundancy
reduced and 2. data is available through one
interface (DBMS interface)

Advantages of a DBMS
 Program and file consistency
 Standardizes the storing of data; so
others can use it easily
 User-friendly
 Easier to deal with [usually provide
friendly interface]
 Improved security
 Control who can access the database

Relational Database Model
 Just a strategy to store and manipulate
data
 The strategy we talked about indirectly refers to
relational model
 Based on relational model
 What is a relational model?
○ it is a method of structuring data using relations,
which are grid-like/matrix-like mathematical
structures consisting of columns and rows
 Table is the physical manifestation of a relation in a
database
 So data are stored in tables (row/column wise) in
Relational Database Models

Relational Database Model
 It is composed of one or more tables [to
represent data]
 Tables also represent the
relations/associations of different related
data
 So here, we have tables of data
 Tables has columns called fields
 Tables are linked/related to other related
tables by common columns/fields
 Primary key/foreign key concept

Relational Model for A
Library
 Books: Book Information
 Id, title, published, price
 Authors: Author Information
 Id, name, SIN, address
 Members: member information
 Id, name, SIN, address, phone, email
 Book-Borrowers:
 Relation between books and members
 Bookid, memberid, date

Features of Relational
DBMS
 Provide easy ways to create tables
 Provide easy ways to create relations
among tables
 Provide ways to insert, update, search data
in a table or from multiple tables
 Provide ways to validate data at insertion
 Provides language such as SQL for data
insertion, update, and search
 Support multiple views of data

Features of Relational
DBMS
 It is easy to create application software
having relational database in the
backend

Usage of Relational DBMS
 Airlines reservation system
 Banking management system
 Online banking system
 Hospital operation management
systems
 Library management system

Creating Databases
 What does it involves?
 In DBMS, usually there is an option to create
database
 It may ask for initial size of the database
 How to increment the size of the database
 Character encoding of the database
 Model to use for creating the database
(relational, object oriented)
 Security/access control for the database
 Path to store the database files
 Then it will create the basic structure of the
database and store it in hardd rive.

Creating Databases
 The basic element of database creation is
fields/columns
 You have to identify the different concepts/object
and relations among concepts [in the system]
 For each, concept/object, you have to identify
fields
 Then create tables for each of the concepts (and
for relations sometimes)
 For each table define the fields/columns
 Identify data types and length for each
column/field and specify it when creating tables

Data Types for Fields
 Numeric
 Byte
 Bit
 Int
 Long
 Double
 float

Data Types for Fields
 Text
 Text
 Char
 Varchar
 Date, DateTime
 Currency

Query Language: SQL
 Types
 Select
○ Selecting data by table fields
 Parameter
○ Query by filling information in dialog bixes
 Crosstab
○ Based on conditions
 Action
○ Delete, update, append

Sorting and Indexing
 Sorting
 Is to arrange/sort data
○ Low to high: Ascending
 1, 2, 3, 4..100
 A ant boy cat
○ High to low: descending
 100,99,98....1
 Cat boy ant a

Indexing
 Create an index (information about the
position) of the data
 Indexing is not actually sorting the data but
keeping track of the locations of the data
 Index can keep track of the data
 by ascending values or in descending values (of
the data)
 i.e. In index file there will be positions/addresses
of the data, the addresses will be kept in the
order of the values of the data

Indexing
 Data
 4
 2
 100
 50
 Index of the data in ascending value of
the data
 2, 1, 4, 3

Indexing
 Advantages
 Can help to find the data faster when index
by one field
 Increases the performance of different
database opertions
 Disadvantages
 More ram used
 Data entry can take time
 When index with multiple fields, data editing
can take longer

Relation Types
 Degree of relations
 Unary -1
 Binary – 2
 Ternary – 3
 Relation Types: among tables
(concepts/objects in the system)
 One to one
 One to Many or Many to One
 Many to Many

Use of Database for
Government
 E-government
 E-governance
 http://en.wikipedia.org/wiki/E-Governance
 E-Governance is the application of Information
and Communication Technology (ICT) for
delivering government services, exchange of
information communication transactions,
integration of various stand-alone systems and
services between Government-to-Citizens
(G2C), Government-to-
Business(G2B),Government-to-Government(
G2G) as well as back office processes and
interactions within the entire government frame
work.

E-government
 E-government
 http://en.wikipedia.org/wiki/E-Government
 E-Government (short for electronic government, also
known as e-gov, Internet government, digital
government, online government, or connected
government) is digital interactions between a government
and citizens (G2C), government and
businesses/Commerce (G2B), government and
employees (G2E), and also between government and
governments /agencies (G2G). Essentially, the e-
Government delivery models can be briefly summed up as
(Jeong, 2007):[1]
 G2C (Government to Citizens)
 G2B (Government to Businesses)
 G2E (Government to Employees)
 G2G (Government to Governments)
 C2G (Citizens to Governments)

Data Security
 Data is important for an organization or
government or a person
 Data should not be able to be accessed
by unauthorized person
 Data when stored in the office or when
transferred over the internet, it should
not be able to be accessed by
unauthorized person such as hackers,
or competitors

Methods to Provide Data
Security
 Restrict access to the computer
(password protect)
 Restrict access to the database
(password protect)
 Use firewalls so that outsiders cannot
access
 While sending data encrypt(unreadbale
format) data

Data Encryption
 Changing/converting the data to
unreadable format while transferring
 Usually using some methods/algorithms
data are encrypted.
 Some encryption methods use keys
 Encryption Ingredients
 Plaintext : text to be sent
 Ciphertext : encryted text
 Encryption algorithm : method to encrypt
 Key : used in encryption or decryption

Encryption Types
 Types
 Secret-key encryption
 Public-key encryption
 Secret-key encryption
 Same key used for encryption and decryption
 Both sender and receiver know the key
 Public-key encryption
 Sender: one key to encrypt : private to sender
 Receiver: another key to decrypt : private to
receiver
 One more key, known to both

Encryption Methods/Algorithms
 Caesar code
 DES
 IDEA
 RSA

Further Study
 Encryption
 http://www.salearningschool.com/searchResult.php?
queryStr=encryption&submit=Search+Database
 Encryption example
○ http://www.salearningschool.com/displayArticle.php?tab
le=Articles&articleID=1355
 Encryption algorithms
 http://www.cse-cst.gc.ca/its-sti/services/crypto-
services-crypto/ca-ac-eng.html
 Choosing encryption methods for SQL Server
 http://technet.microsoft.com/en-
us/library/ms345262.aspx

Our Addresses
 Trudelle Street, Toronto, Canada
 sayed@justetc.com
 Shimultuly, Gazipur, Bangladesh
 Justetc Computers
 Habib Complex, 2nd Floor
 rafik@justetc.com (01942747702)

References
 DBMS Theory
 http://www.salearningschool.com/index.php?table=Articles
&categoryID=6&category=DBMS%20Theory
 Database Systems
 http://www.salearningschool.com/index.php?table=Articles
&categoryID=2&category=Database%20Systems
 MySQL DBMS
 http://www.salearningschool.com/searchResult.php?query
Str=mysql&submit=Search+Database
 Indexing vs Sorting
 http://docs.acl.com/acl/920/index.jsp?topic=/com.acl.user_
guide.help/data_analysis/c_sorting_versus_indexing.html

Database management system

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