Database Management Systems (DBMS) (IS212) PDF

Database Management Systems (DBMS) (IS212) Information Systems Department Faculty of Computers and Information Minia University Weighing of Assessment: Mid Term Examination 10 % Final Term Examination 60 % Oral Examination 10 % Practical Examination 10 % Se...

Database Management Systems (DBMS) (IS212) Information Systems Department Faculty of Computers and Information Minia University Weighing of Assessment: Mid Term Examination 10 % Final Term Examination 60 % Oral Examination 10 % Practical Examination 10 % Semester Work 10 % Total 100 % 2 Course outline Introduction to Database The Relational Data Model and Relational Database Constraints Data Modeling Using the Entity Relationship (ER) Model Basic SQL Database Design Theory and Normalization 3 Chapter 1: Introduction to Database Examples of Database Applications ❑ Purchases from the supermarket ❑ Purchases using your credit card ❑ Booking a holiday at the travel agents ❑ Using the local library ❑ Taking out insurance ❑ Renting a video ❑ Using the Internet ❑ Studying at university 5 Definitions of Database ❑ Def 1: Database is an organized collection of logically related data ❑ Def 2: A database is a shared collection of logically related data that is stored to meet the requirements of different users of an organization ❑ Def 3: A database is a self-describing collection of integrated records ❑ Def 4: A database models a particular real world system in the computer in the form of data 6 Definitions ❑ Data: Referred to facts concerning objects and events that could be recorded and stored on computer media ❑ Structured: numbers, text, dates ❑ Unstructured: images, video, documents ❑ Information: data processed to increase knowledge in the person using the data ❑ Metadata: data that describes the properties and context of user data 7 What is a Database ❑ Shared collection of logically related data (and a description of this data), designed to meet the information needs of an organization. ❑ System catalog (metadata) provides description of data to enable program–data independence. ❑ Logically related data comprises entities, attributes, and relationships of an organization’s information. 8 Figure 1-1a Data in Context Context helps users understand data 9 Descriptions of the properties or characteristics of the data, including data types, field sizes, allowable values, and data context 10 The concept of a shared organizational database Management Marketing Product Planning Control Sales Development Corporate Database Accounting Manufacturing Accounts Accounts Scheduling Production Receivable Payable 11 File Processing System ❑ A collection of application programs that perform services for the end- users such as production of reports ❑ Each program defines and manages its own data 12 File Processing Systems Library Examination Registration Library Examination Registration Applications Applications Applications Library Examination Registration Data Data Data Files Files Files Program and Data 13 Interdependence  File Processing Systems Library Examination Registration Reg_Number Reg_Number Reg_Number Name Name Name Father Name Address Father Name Books Issued Class Phone Fine Semester Address Grade Class 14 Files Based Processing 15 Disadvantages of File Processing ❑ Program-Data Dependence ❑ File structure is defined in the program code. ❑ All programs maintain metadata for each file they use ❑ Duplication of Data (Data Redundancy) ❑ Different systems/programs have separate copies of the same data Same data is held by different programs. Wasted space and potentially different values and/or different formats for the same item. ❑ Limited Data Sharing ❑ No centralized control of data ❑ Programs are written in different languages, and so cannot easily access each other’s files. 16 Disadvantages of File Processing ❑ Lengthy Development Times ❑ Programmers must design their own file formats ❑ Excessive Program Maintenance ❑ 80% of of information systems budget ❑ Vulnerable to Inconsistency ❑ Change in one table need changes in corresponding tables as well otherwise data will be inconsistent 17 SOLUTION: The DATABASE Approach ❑ Central repository of shared data ❑ Data is managed by a controlling agent ❑ Stored in a standardized, convenient form This requires a Database and Database Management System (DBMS) 18  Advantages of Database Approach Library Examination Registration Library Examination Registration Applications Applications Applications Database Management System - Data Sharing - Data Independence - Controlled Redundancy University - Better Data Integrity Students Database 19 Database Management System Database Management System (DBMS): A software package/ system to facilitate the creation and maintenance of a computerized database. Database System: The DBMS software together with the data itself. Sometimes, the applications are also included. 20 Simplified database system environment 21 Typical DBMS Functionality Define a particular database in terms of its data types, structures, and constraints Construct or Load the initial database contents on a secondary storage medium Manipulating the database: Retrieval: Querying, generating reports Modification: Insertions, deletions and updates to its content Accessing the database through Web applications Processing and Sharing by a set of concurrent users and application programs – yet, keeping all data valid and consistent 22 Typical DBMS Functionality Other features: Protection or Security measures to prevent unauthorized access “Active” processing to take internal actions on data Presentation and Visualization of data Maintaining the database and associated programs over the lifetime of the database application Called database, software, and system maintenance Example of a Database (with a Conceptual Data Model) Mini-world for the example: Part of a UNIVERSITY environment. Some mini-world entities: STUDENTs COURSEs SECTIONs (of COURSEs) (academic) DEPARTMENTs INSTRUCTORs Slide 1- 24 Example of a Database (with a Conceptual Data Model) 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 Example of a simple database Thanks 27