DATABASE MANAGEMENT SYSTEM

Sayed AhmedComputer Engineering, BUET, BangladeshMSc, Computer Science, U of Manitoba, Canada

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Syllabus and Learning Objectives

Syllabus and Learning Objectives

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

ImportanceMethods

Querying Database: Query Language: SQL

Uses of Databases

What is a Database? Database means

Data storageA good/organized/efficient way of storing dataYou 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 databaseNot much, databases also store data in filesHowever, 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 fileAll bank account informationAll employee informationAll account holder informationAll branch and department informationYou 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 wayThen we can call this software to be a DBMSDBMSes 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 databaseAllocate 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

AccuracyCan 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-friendlyEasier 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 modelWhat 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 rowsTable is the physical manifestation of a relation in a

databaseSo 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/fieldsPrimary 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 membersBookid, memberid, date

Relational Model

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 databaseIt may ask for initial size of the databaseHow to increment the size of the databaseCharacter encoding of the databaseModel to use for creating the database (relational,

object oriented)Security/access control for the databasePath to store the database filesThen 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

ByteBitIntLongDoublefloat

Data Types for Fields Text

TextCharVarchar

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..100A ant boy cat

○ High to low: descending100,99,98....1Cat 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

4210050

Index of the data in ascending value of the data2, 1, 4, 3

Indexing Advantages

Can help to find the data faster when index by one field

Increases the performance of different database opertions

DisadvantagesMore ram usedData entry can take timeWhen index with multiple fields, data editing

can take longer

Indexing vs Sorting

Relation Types Degree of relations

Unary -1Binary – 2Ternary – 3

Relation Types: among tables (concepts/objects in the system)One to oneOne to Many or Many to OneMany to Many

Use of Database for Government E-government E-governance

http://en.wikipedia.org/wiki/E-GovernanceE-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 sentCiphertext : encryted textEncryption algorithm : method to encryptKey : used in encryption or decryption

Encryption Types Types

Secret-key encryptionPublic-key encryption

Secret-key encryptionSame key used for encryption and decryptionBoth sender and receiver know the key

Public-key encryptionSender: one key to encrypt : private to senderReceiver: another key to decrypt : private to

receiverOne 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?table=Articles&articleID=1355

Encryption algorithmshttp://

www.cse-cst.gc.ca/its-sti/services/crypto-services-crypto/ca-ac-eng.html

Choosing encryption methods for SQL Serverhttp://

technet.microsoft.com/en-us/library/ms345262.aspx

Our Addresses Trudelle Street, Toronto, Canada

sayed@justetc.com Shimultuly, Gazipur, Bangladesh

Justetc ComputersHabib 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?queryStr=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