Introduction to Database Systems PDF

Introduction to Database Systems Week1: Introduction and Basic Concepts  Agenda  Basic Concepts  Introduction to Database Systems  Application Areas of DBMS  Examples of DBMS  DBMS Functionality  Database Characteristics 2  Basic Concepts...

Introduction to Database Systems Week1: Introduction and Basic Concepts  Agenda  Basic Concepts  Introduction to Database Systems  Application Areas of DBMS  Examples of DBMS  DBMS Functionality  Database Characteristics 2  Basic Concepts ▸In computing, data is translating information into an efficient form as known facts to be processed, recorded, and stored by a computer system. ▸This information may have the form of text documents, images, audio, or other data types. ▸In other words, information is data that has been processed into an implicit meaningful form, e.g., Student Information. Figure 1: Transforming data into information 3  Basic Concepts ▸A database is an organized collection of related sets of data that are managed to enable the user to view the Database System complete collection or any logical subset of the collection as a single unit. ▸Database Management System (DBMS) is a software package/system to create and maintain a computerized database. ▸A database system is considered as a computerized record-keeping system, including the DBMS software and the data itself. Figure 2: Database, DBMS, and database Systems 4  Introduction to Database Systems ▸The database is a kind of repository for collecting computerized data files and allow users to perform a variety of operations, such as: ▹adding new files to the database ▹inserting data into existing files ▹retrieving data from existing files ▹changing data in existing files ▹deleting data in existing files ▹removing existing files from the database 5  Application Areas of DBMS ▸ Airlines: For reservations and schedule information. ▸ Banking: For customer information, accounts loans and banking transactions. ▸ Universities: For student information, course registrations and grades. ▸ Credit card transactions: For purchases on credit cards and generation of monthly statements. ▸ Telecommunications: For keeping records of calls, generating monthly bills, maintaining balances on prepaid calling cards and storing information about the communication networks. ▸ Sales: For customer, product and purchase information. ▸ Manufacturing: For management of supply chain and for tracking production of items in factories, inventories of items in warehouses/stores and orders for items. ▸ Human Resources: For information about employees, salaries, payroll taxes and benefits and for generation of paychecks. ▸6 Web based services: For taking web users feedback, responses, resource sharing, etc.  Examples of DBMS ▸MySQL Database: It was founded in the year 1995. MySQL was acquired by Sun Microsystems in 2008 and the sun Microsystems was acquired by Oracle after two years. MySQL is one of the largest open-source companies in the world and is popular due to its high level of efficiency, reliability and cost. ▸MS-Access: It was developed by Microsoft and this computer-based application is used to form as well as create the databases on the desktop of the computers. It can be used for personal work and for small scale business that required a database. ▸Oracle database: It is the fourth relational database management system which is developed by Oracle Corporation. Oracle database is useful for storing a large amount of data, especially by large organizations. ▸Microsoft SQL Server: It is an RDBMS from Microsoft company which creates computer databases for MS- Windows. Based on customer’s requirements, Microsoft has developed various versions of SQL Server. 7  DBMS Functionality ▸Define a database in terms of data types, structures, and constraints. ▸Construct or Load the Database on a secondary storage medium. ▸Manipulating the database querying, generating reports, insertions, deletions, and modifications to its content. ▸Concurrent Processing and Sharing by a set of users and programs while keeping the data's validity and consistency. ▸Other features: ▹Protection or Security measures to prevent unauthorized access. ▹Active processing to take internal actions on data. 8 ▹Presentation and Visualization of data  University Database Example ▸Mini-world are some parts of the real world in which data is stored in a database. ▸Mini-world for the example is part of the UNIVERSITY environment. ▸Some mini-world entities: ▹STUDENTs ▹COURSEs ▹SECTIONs (of COURSEs( ▹(academic) DEPARTMENTs ▹INSTRUCTORs 9  University Database Example ▸Some mini-world relationships: ▹SECTIONs are of specific COURSEs ▹STUDENTs take SECTIONs ▹COURSEs have prerequisite COURSEs ▹INSTRUCTORs teach SECTIONs ▹COURSEs are offered by DEPARTMENTs ▹STUDENTs major in DEPARTMENTs 10  Library Loan Database Example ▸Figure 3 shows the database structure and sample data for a database that maintains information concerning borrowers, books, loans, and reservations in a library loan system. Figure 3: Sample data in relational form for Library Loan Database 11  Database Characteristics ▸Self-describing nature of a database system ▹A DBMS catalog stores the description of the database. ▹This description is called meta-data, which allows the DBMS software to work with different databases. ▸Insulation between programs and data ▹Called program-data independence, that allows changing data storage structures and operations without having to change the DBMS access programs. 12  Database Characteristics ▸Data Abstraction ▹A data model is used to hide storage details and present the users with a conceptual view of the database. ▸Support of multiple views of the data ▹Each user may see a different view of the database, which describes only the data of interest to that user. 13  Database Characteristics ▸Sharing of data and multiuser transaction processing ▹Allowing a set of concurrent users to retrieve and to update the database. ▹Concurrency control within the DBMS guarantees that each transaction is correctly executed or completely aborted. ▹(OLTP)Online Transaction Processing is a major part of database applications. 14