Introduction To Computers

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1 Introduction To Computers Chapter No 7 Introduction To Databases Overview Introduction to database To make use of information, you have to be able to find the information Data files and databases are no longer confined to big-company mainframe computers Sophisticated database capability can be right on your desktop Access to the Internet expands your access to data ITC - Chapter 7 Introduction to Databases 2 1

2 Databases The database has become an integral part of almost every human's life. Without it, many things we do would become very tedious, perhaps impossible tasks. Banks, universities, and libraries are three examples of organizations that depend heavily on some sort of database system. On the Internet, search engines, online shopping, and even the website naming convention ( would be impossible without the use of a database. A database that is implemented and interfaced on a computer is often termed a database server. ITC - Chapter 7 Introduction to Databases 3 What is a Database Character: usually a byte i.e. 8 bits Example. A, 8, $, Field: Unit of data containing one or more characters Example. NAME, DOB Record: A collection of related fields NAME EMPID DOB Imran Khalid ITC - Chapter 7 Introduction to Databases 4 2

What is a Database Character Field Record File Database Single letter, number or special character A set of related characters Collection of related fields Collection of related

3 What is a Database Character Field Record File Database Single letter, number or special character A set of related characters Collection of related fields Collection of related records Collection of related files Example. Files of all department in an organization. ITC - Chapter 7 Introduction to Databases 5 Field Record ITC - Chapter 7 Introduction to Databases 6 3

4 Professional Address Book Table ITC - Chapter 7 Introduction to Databases 7 Examples of Databases Oracle SQL Server Sybase Access FoxPro ITC - Chapter 7 Introduction to Databases 8 4

5 Need of Databases Sharing- Sharing of information between departments Security- Security can restrict user access only to their need to know Data Redundancy- Data redundancy is reduced, saving on storage costs Data Integrity- Data integrity reduced likelihood of inconsistent data ITC - Chapter 7 Introduction to Databases 9 Types of Databases Shared Databases: They are shared by users of one company or organization. Usually found in LANs Users are linked through terminals or WS Stored on One Computer ITC - Chapter 7 Introduction to Databases 10 5

6 Types of Databases Distributed Databases: Stored on different computers in different locations connected by a client-sever network. Example. Chain stores ITC - Chapter 7 Introduction to Databases 11 Database Administrator (DBA) A person managing the database is a DBA There are a number of factors the DBA should consider before implementing databases in a distributed system. Many of the planning decisions will require the cooperation and transfer of information between the network administrator and the DBA. There are also operating system-specific issues the DBA must consider when planning to distribute databases on certain platforms. ITC - Chapter 7 Introduction to Databases 12 6

7 Major tasks of a DBA DB design, Implement and operate Co-ordination with users DB Security Eg. Access Rights Backup and Recovery Performance Monitoring ITC - Chapter 7 Introduction to Databases 13 What is a Key Field Key field is also called Primary Key It is that field that contains unique data used to identify a record so that it can be easily retrieved and processed. This also reduces confusion with other records. Example. NIC number, EmpNo. ITC - Chapter 7 Introduction to Databases 14 7

8 Data Files and its Types Data files are often called document files They contain data, not programs Eg. Files with.doc extension They are of two types: 1. Master File 2. Transaction File ITC - Chapter 7 Introduction to Databases 15 Types of Data Files Master File: It contains relatively permanent records that are generally updated periodically. Example. All Students of SSUET and their Roll # Transaction Files: Temporary holding file that holds changes to be made to the master file. Example. New Students New Students ITC - Chapter 7 Introduction to Databases 16 8

9 File Management System A software to create, retrieve and manipulate files. It has many disadvantages such as: 1. Data Redundancy: Same data field in many files 2. Lack of Data Integrity: Data Integrity means accuracy of data 3. Poor Data Sharing ITC - Chapter 7 Introduction to Databases 17 Database Management System (DBMS) A DBMS allows users to access and manage the data collected in a database. Data management tasks (all done through the DBMS) can be divided into three categories: Entering data into the database. Sorting (rearranging) the data in the database. Obtaining subsets of the data for use ITC - Chapter 7 Introduction to Databases 18 9

10 Working With a Database Creating Database Tables Viewing Records Sorting Records Querying a Database Generating Reports ITC - Chapter 7 Introduction to Databases 19 ITC - Chapter 7 Introduction to Databases 20 10

11 DBMS Components ITC - Chapter 7 Introduction to Databases 21 DBMS Components ITC - Chapter 7 Introduction to Databases 22 11

12 Role of DBMS ITC - Chapter 7 Introduction to Databases 23 ITC - Chapter 7 Introduction to Databases 24 12

13 DBMS Advantages and Disadvantages Advantages Additional Capabilities Sorting Query Integrity Checking Easy access to data Reduce Data Redundancy Improve Data Integrity Increase User Productivity Increase Security Disadvantages Few graphical or statistical capabilities Proprietary formats may limit archival quality of data Require expertise and resources to administer Cost Issue ( Installing and maintenance of a database ) ITC - Chapter 7 Introduction to Databases 25 Types of DBMS Hierarchical DBMS Network DBMS Relational DBMS Object Oriented DBMS ITC - Chapter 7 Introduction to Databases 26 13

14 Hierarchical DBMS Adding new fields to DB record requires that the entire DB to redefined. ITC - Chapter 7 Introduction to Databases 27 Hierarchical DBMS Fields or records structured in nodes Viewed as branches of an upside-down tree Low-level record is called a Child High-Level record is called a Parent Top Record is called the Root. All records are dependent Data is stored as a tree Structure is restrictive Difficult to re-order data They have One-to-many relationship Hierarchical DBMSs are seldom encountered today ITC - Chapter 7 Introduction to Databases 28 14

15 Network DBMS ITC - Chapter 7 Introduction to Databases 29 Records of a Network DBMS ITC - Chapter 7 Introduction to Databases 30 15

Network DBMS In Network DBMS each child record can have more than one parent record Network DBMSs have more relationships (i.e., not limited to one tree structure) Data is related by pointers Child record is also called a Member.

16 Network DBMS In Network DBMS each child record can have more than one parent record Network DBMSs have more relationships (i.e., not limited to one tree structure) Data is related by pointers Child record is also called a Member. Parent record is called an Owner. They have many-to-many relationships Network DBMSs are seldom encountered today ITC - Chapter 7 Introduction to Databases 31 Relational DBMS ITC - Chapter 7 Introduction to Databases 32 16

17 Relational DBMS No pre-determined access paths Data stored in a collection of columns and rows called a table, or a relation Tables may be electronically linked via a key field containing common data Easy to add, delete and modify the data and the table structures More flexible then Hierarchical and Network DBMS. Example: Access, Paradox ITC - Chapter 7 Introduction to Databases 33 Relational DBMS Currently the standard Data is stored in tables Tables are related by shared elements Tables are called Relations ( files ). The rows or records are called Tuples The columns or fields are called Attributes. ITC - Chapter 7 Introduction to Databases 34 17

18 Advantages of RDBMS much more flexible faster to update easier to modify better consistency faster retrieval fancier search capabilities cheap ITC - Chapter 7 Introduction to Databases 35 Object Oriented DBMS ITC - Chapter 7 Introduction to Databases 36 18

19 Object Oriented DBMS ( OODBMS) Object Oriented DBMS can handle any type of data not only numerical and text data but also graphics, audio and video too. Object Oriented DBMS uses objects as elements within database file Major areas of Object Oriented DBMS development Medical Information System Engineering Information System Geographical Information System Education Information System ITC - Chapter 7 Introduction to Databases 37 Why do we need OODBMS The increased emphasis on process integration is a driving force for the adoption of object-oriented database systems. For example, the Computer Integrated Manufacturing (CIM) area is focusing heavily on using object-oriented database technology as the process integration framework. Advanced office automation systems use object-oriented database systems to handle hypermedia data. Hospital patient care tracking systems use object-oriented database technologies for ease of use. All of these applications are characterized by having to manage complex, highly interrelated information, which is a strength of object-oriented database systems. ITC - Chapter 7 Introduction to Databases 38 19

20 OODBMS ITC - Chapter 7 Introduction to Databases 39 Objects in an OODBMS ITC - Chapter 7 Introduction to Databases 40 20

21 ITC - Chapter 7 Introduction to Databases 41 Advantages of OODBMS Multimedia data is accessible Group data and process Understand complex objects Easy to maintain and change Improve productivity ITC - Chapter 7 Introduction to Databases 42 21

Topics covered 10/12/2015. Pengantar Teknologi Informasi dan Teknologi Hijau. Suryo Widiantoro, ST, MMSI, M.Com(IS)

Topics covered 10/12/2015. Pengantar Teknologi Informasi dan Teknologi Hijau. Suryo Widiantoro, ST, MMSI, M.Com(IS) Pengantar Teknologi Informasi dan Teknologi Hijau Suryo Widiantoro, ST, MMSI, M.Com(IS) 1 Topics covered 1. Basic concept of managing files 2. Database management system 3. Database models 4. Data mining