Introduction to Databases By Faraz Ahmed

Recommended Text/ Reference Books Fundamentals of Database Systems, 3rd Edition by Elmasri & Navathe Database System Concepts 3rd Edition by Abraham Silbershatz, Henery F. Korth, Sudarshan An introduction to Database Systems By C.J. Date Faraz Ahmed

Programming Skills Front-End Development Back-End Development ASP.NET using C#/VB.Net, C++, PHP Back-End Development MS-Access, Oracle 9i or higher, MS SQL Server Documentation ER-Win, Visio, MS-Word Faraz Ahmed

Top Database Groups Academia: 1) Stanford University, 2) University of Wisconsin, Madison, 3) University of California, Berkeley, 4) University of Maryland, College Park, 5) University of Washington. Research Labs: 1) IBM Almaden Research Lab, 2) AT&T Research Labs, 3) Microsoft Research Lab, 4) Lucent Technologies. Database Products: 1) Oracle, 2) IBM DB2, 3) MySQL, 4) Sybase, 5) MS SQL Server, 6) Informix. Faraz Ahmed

Types of Databases Flat Files Hierarchical Relational Object Relational Object Oriented Web Enabled (Online DBs) Faraz Ahmed

Overview Data: Known facts that can be recorded Database: Collection of Integrated data Typically models a real-world “enterprise” DBMS: A software system designed to store, manage, and facilitate access to databases. Faraz Ahmed

Data vs. Information Data: Raw facts/Un-processed information But they are building blocks for information Information: Data Processed to reveal its meaning Information is meaningful In today’s world, accurate, relevant and timely information is the key to good decision making Good decision making is key to survival in today’s competitive and global environment Faraz Ahmed

Data and Information … Data: is known recorded facts which has specific meanings or interpretation. Example: the numbers 10.5, 22, and 119 are data Information: is a precise, understandable and specific representation of data. Example: The temperature of room 119 in building 22 is 10.5, is an information Knowledge: is something which is derived or inferred from available information using some level of intelligence. Example: Based on experience, the above information can be used to infer that the room is quite cold and could cause some inconvenience if we work on that room for a long period of time with out wearing worm clothes. Faraz Ahmed

The Need Faraz Ahmed

Files and Databases Files: A collection of records or documents dealing with one organization, person, area, or subject. It could either be: Computer files Manual files (Paper) Database: A collection of similar records with relationships between records. Statistical, Business Data Faraz Ahmed

Database vs. File Systems

Database A database is collection of stored operational data used by application systems of some particular enterprise (C.J. Date) Paper Database Still contain a large portion of world's knowledge File Processing Systems Early batch processing of business data Database Management Systems (DBMS) Will cover in detail Faraz Ahmed

File Processing Systems Collection of application programs that performs services for the end-users (e.g. Reports) Each program defines and maintains its own data Faraz Ahmed

File Processing Systems Faraz Ahmed

File Processing Systems Faraz Ahmed

-- File-Based Approach User 1 Application programs Data Data Application programs User 2 Faraz Ahmed

Limitations of File-based Approach Separation and isolation of data Each program maintains its own set of data. Users of one program may be unaware of potentially useful data held by other programs. Duplication of data Same data is held by different programs. Wasted space and potentially different values and/or different formats for the same item. Atomicity of updates Failure may lead database to an inconsistent state with partial updates carried out E.g. Transfer of funds from one account to another should either be complete or incomplete, no in-between state Faraz Ahmed

Limitations of File-based Approach Data dependence File structure is defined in the program code. Incompatible file formats Programs are written in different languages, and so cannot easily access each others files. Integrity Problems Integrity constraints (e.g. account_balance > 0) became “buried” in program code rather than being stated explicitly Hard to add new constraint or update existing one File in the folder cannot keep such conditions difficult to enforce/add/change consistency constraints in a file processing system Faraz Ahmed

Limitations of File-based Approach Fixed Queries/Proliferation of application programs Programs are written to satisfy particular functions. Any new requirement needs a new program. Data Redundancy and Inconsistency Multiple file formats, and duplication of information in different files Difficulty in Accessing Data Need to write a new program for accessing new data Faraz Ahmed

Database Approach Overcomes problems associated with file-system based approach Central repository of shared data The database holds not only the data but also a description of the data. Data dictionary, or metadata A central location where data descriptions are stored. Data about data Program-data independence Faraz Ahmed

Advantages of the Database Approach Program-data independence The separation of data descriptions from the application programs that use the data. Allows the data to change without changing the application programs. No or Planned data redundancy Improved data consistency Improved data sharing Enforcement of standards Faraz Ahmed

DBMS is a Package Faraz Ahmed

Database Management System (DBMS) DBMS is a software package that enables user to create and maintain databases. It facilitates: Defining a database that involves specifying the data types, structures, and constraints for the data to be stored in the database. Constructing a database which is the process of storing the data. Manipulating a database such as functions of querying and sharing the database objects, updating the database, and generating reports from the data. Database and DBMS software together constitute a database system. Faraz Ahmed

Examples DBMS Oracle IBM DB2 Ingress Teradata MS SQL Server MS Access MySQL etc. Faraz Ahmed

Database Management System (DBMS) Features A Software Package that enables users to define, create, maintain, and control access to the database. Data Definition Language (DDL) Data Manipulation Language (DML) Control access: Security, integrity, concurrent access, recovery, support for data communication, etc. Utility services File import/export, monitoring facilities, code generator, report writer, etc. Support Ad Hoc queries Faraz Ahmed

DBMS Architecture Form Processing & Report Processing Applications are build by using VB, DOT Net or PHP programming. Reports can be developed using Crystal Reports tool. Query Processing can be managed by using vendors SQL tool or 3rd party tools such As TOAD, SQL Developer Faraz Ahmed

Data Accessing using DBMS 2-tiers & 3-tiers Architectures Faraz Ahmed

Database Management System A software system that is used to create, maintain, and provide controlled access to user databases Order Filing System Central database Contains employee, order, inventory, pricing, and customer data Invoicing System DBMS Payroll System DBMS manages data resources like an operating system manages hardware resources Faraz Ahmed

Database System Environment Faraz Ahmed

DBMS Benefits Minimal data redundancy Consistency of data Integration of data Sharing of data Ease of application development Uniform security, privacy and integrity controls Data accessibility and responsiveness Reduced program maintenance Data independence Faraz Ahmed

DBMS related Applications SQL Forms/ Reports Web/ Portal GUI Client-Server (VB, C++, Java, Mobile) SAP/ OracleApps BI Applications (SAS, OracleWarehousing) Case Tools (Toad Modeler, Enterprise Architect, VISIO etc) Faraz Ahmed

Components of DBMS Environment Faraz Ahmed

Components of DBMS Environment Hardware Can range from a PC to a network of computers Software DBMS, operating system, network software (if necessary) and also the application programs Data Used by the organization and a description of this data called schema Faraz Ahmed

Components of DB Environment … Procedures Instructions and rules that should be applied to the design and use of the database and DBMS People Faraz Ahmed

Database Professionals Database implementers Build modules that go inside the DBMS Database application developers Build application that run on top of the DBMS, and are used by end-users to interact with their data. Database Administrators Create database schema Maintain and tune the DBMS engine Maintain and tune the data in the DBMS Corporations need them ($$$) Faraz Ahmed

Roles/ Jobs in the Database Environment Data Administrator (DA) Database Administrator (DBA) Database Designers (Logical and Physical) Applications Programmer Database Developer Database Analyst End users (Naive and sophisticated) Faraz Ahmed

Forms & Reports Faraz Ahmed Any data entry activity with data insert, update, search and delete constitutes a concept of Form. Forms can be developed using VB Dot Net, Dot Net, Oracle Form Developers S/W Reports: Read only, print purposes and no data change (open in pdf). Examples: Electric/ gas bills, degree transcript and automatic letter generated. Report development programming can be managed using Dot Net, Crystal Report, Oracle Report Developers S/W visual software programming. Faraz Ahmed

-- Database Approach User 1 DBMS User 2 Application programs Database Faraz Ahmed

Interaction of DBMS with Files Faraz Ahmed

Evolution of DB Systems Faraz Ahmed