Chapter 1 Essay

Chapter 1 Essay Chapter 1 Essay Copyright  © 2007 Ramez Elmasri and Shamkant B. Navathe Slide 1- 1 Chapter 1 Introduction: Databases and Database Users Copyright  © 2007 Ramez Elmasri and Shamkant B. Navathe Outline ï  ® ï  ® ï  ® ï  ® ï  ® ï  ® ï  ® ï  ® Types of Databases and Database Applications Basic Definitions Typical DBMS Functionality Example of a Database (UNIVERSITY) Main Characteristics of the Database Approach Database Users Advantages of Using the Database Approach When Not to Use Databases Copyright  © 2007 Ramez Elmasri and Shamkant B. Navathe Slide 1- 3 Types of Databases and Database Applications ï  ® Traditional Applications: ï  ® ï  ® More Recent Applications: ï  ® ï  ® ï  ® ï  ® ï  ® ï  ® ï  ® Numeric and Textual Databases Multimedia Databases Geographic Information Systems (GIS) Data Warehouses Real-time and Active Databases Many other applications First part of book focuses on traditional applications A number of recent applications are described later in the book (for example, Chapters 24,26,28,29,30) Copyright  © 2007 Ramez Elmasri and Shamkant B. Navathe Slide 1- 4 Basic Definitions ï  ® ï  ® ï  ® ï  ® ï  ® Database: ï  ® A collection of related data. Data: ï  ® Known facts that can be recorded and have an implicit meaning. Mini-world: ï  ® Some part of the real world about which data is stored in a database. For example, student grades and transcripts at a university. Database Management System (DBMS): ï  ® A software package/ system to facilitate the creation and maintenance of a computerized database. Database System: ï  ® The DBMS software together with the data itself. Sometimes, the applications are also included. Copyright  © 2007 Ramez Elmasri and Shamkant B. Navathe Slide 1- 5 Simplified database system environment Copyright  © 2007 Ramez Elmasri and Shamkant B. Navathe Slide 1- 6 Typical DBMS Functionality ï  ® ï  ® ï  ® 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: ï  ® ï  ® ï  ® ï  ® 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 Copyright  © 2007 Ramez Elmasri and Shamkant B. Navathe Slide 1- 7 Typical DBMS Functionality ï  ® Other features: ï  ® ï  ® ï  ® ï  ® Protection or Security measures to prevent unauthorized access â€Å"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 ï  ® Called database, software, and system maintenance Copyright  © 2007 Ramez Elmasri and Shamkant B. Navathe Slide 1- 8 Example of a Database (with a Conceptual Data Model) ï  ® Mini-world for the example: ï  ® ï  ® Part of a UNIVERSITY environment. Some mini-world entities: ï  ® ï  ® ï  ® ï  ® ï  ® STUDENTs COURSEs SECTIONs (of COURSEs) (academic) DEPARTMENTs INSTRUCTORs Copyright  © 2007 Ramez Elmasri and Shamkant B. Navathe Slide 1- 9 Example of a Database (with a Conceptual Data Model) ï  ® Some mini-world relationships: ï  ® ï  ® ï  ® ï  ® ï  ® ï  ® ï  ® SECTIONs are of specific COURSEs STUDENTs take SECTIONs COURSEs have prerequisite COURSEs INSTRUCTORs teach SECTIONs COURSEs are offered by DEPARTMENTs STUDENTs major in DEPARTMENTs Note: The above entities and relationships are typically expressed in a conceptual data model, such as the ENTITY-RELATIONSHIP data model (see Chapters 3, 4) Copyright  © 2007 Ramez Elmasri and Shamkant B. Navathe Slide 1- 10 Example of a simple database Copyright  © 2007 Ramez Elmasri and Shamkant B. Navathe Slide 1- 11 Main Characteristics of the Database Approach ï  ® Self-describing nature of a database