Module 1 Databases and Database Users PDF

‫اﻟﺠﺎﻣﻌﺔ اﻟﺴﻌﻮدﻳﺔ اﻻﻟﻜﺘﺮوﻧﻴﺔ‬ ‫اﻟﺠﺎﻣﻌﺔ اﻟﺴﻌﻮدﻳﺔ اﻻﻟﻜﺘﺮوﻧﻴﺔ‬ ‫‪26/12/2021‬‬ College of Computing and Informatics IT244 Introduction to Database Introduction to Database Databases and Database Users Contents 1. Databases and Database Users Weekly Learning Outcomes 1. Explain the basic c...

‫اﻟﺠﺎﻣﻌﺔ اﻟﺴﻌﻮدﻳﺔ اﻻﻟﻜﺘﺮوﻧﻴﺔ‬ ‫اﻟﺠﺎﻣﻌﺔ اﻟﺴﻌﻮدﻳﺔ اﻻﻟﻜﺘﺮوﻧﻴﺔ‬ ‫‪26/12/2021‬‬ College of Computing and Informatics IT244 Introduction to Database Introduction to Database Databases and Database Users Contents 1. Databases and Database Users Weekly Learning Outcomes 1. Explain the basic concepts of Database. 2. Explain types of Database Users. Required Reading 1. Chapter 1: The Complete chapter (Fundamentals of Database Systems, Global Edition, 7th Edition (2017) by Ramez Elmasri & Shamkant Navathe) Recommended Reading Database System Concepts and Architecture: https://cs.uwaterloo.ca/~tozsu/courses/CS338/lectures/14%20DB%20System.pdf NoSQL databases: https://courses.cs.vt.edu/cs4604/Spring21/pdfs/12-nosql.pdf This Presentation is mainly dependent on the textbook: Fundamentals of Database Systems, Global Edition, 7th Edition (2017) by Ramez Elmasri & Shamkant Navathe  Databases and Database Users Chapter 1 Outline n Types of Databases and Database Applications n Basic Definitions n Typical DBMS Functionality n Example of a Database (UNIVERSITY) n Main Characteristics of the Database Approach n Types of Database Users n Advantages of Using the Database Approach n When Not to Use Databases Basic Definitions (1) n Data n Known facts that can be recorded and have an implicit meaning. n Example: the names, telephone numbers, and addresses of the people you know n Database n A collection of related data in a DBMS. n Example: the list of names and addresses, and computerized catalog of a large library n Defining a database n Involves specifying the data types, structures, and constraints of the data to be stored in the database. n Meta-data n The database definition or descriptive information is also stored by the DBMS in the form of a database catalog or dictionary. n Database Management System (DBMS) n A computerized system that enables users to create and maintain a database. It is a general- purpose software system that facilitates the processes of defining, constructing, manipulating, and sharing databases among various users and applications. n Database System n The database and DBMS software together; Sometimes, the application programs and interfaces are also included. Basic Definitions (2) n Manipulating a database n Includes querying the database to retrieve specific data, updating the database, and generating reports from the data. n Sharing a database n Allows multiple users and programs to access the database simultaneously. n Application program n Accesses the database by sending queries or requests for data to the DBMS. n Query n A query causes some data to be retrieved from the database. n Transaction n May cause some data to be read from and some data to be written into the database. n Protection n May includes system protection against hardware or software malfunction (or crashes) and security protection against unauthorized or malicious access. n Maintenance n A typical large database has a life cycle of many years, so the DBMS must be allowing the system to evolve as requirements change over time. Simplified database system environment Implicit Properties of a Database n A database represents some aspect of the real world, called the miniworld or the universe of discourse (UoD). Changes to the miniworld are reflected in the database. n A database is a logically coherent collection of data with some inherent meaning. A random assortment of data cannot correctly be referred to as a database. n A database is designed, built, and populated with data for a specific purpose. It has an intended group of users and some preconceived applications in which these users are interested. Example of a Database UNIVERSITY Application (1) n Mini-world for the example: n Part of a UNIVERSITY environment. n Some mini-world entities: n INSTRUCTORs n STUDENTs n DEPARTMENTs n COURSEs n SECTIONs (of COURSEs) n Some mini-world relationships: n SECTIONs are of specific COURSEs n STUDENTs take SECTIONs n COURSEs have prerequisite COURSEs n INSTRUCTORs teach SECTIONs n COURSEs are offered by DEPARTMENTs n STUDENTs major in DEPARTMENTs n Note: The above entities and relationships are typically expressed in the ENTITY- RELATIONSHIP data model Example of a Database UNIVERSITY Application (2) Example of a Database UNIVERSITY Application (3) Typical DBMS Functionality n Define a particular database in terms of its data types, structures, and constraints n Construct or Load the initial database contents on a secondary storage medium n Manipulating the database: n Retrieval: Querying, generating reports n Modification: Insertions, deletions and updates to its content n Accessing/changing the database through Web applications n Processing and Sharing by a set of concurrent users and application programs n Protection or Security measures to prevent unauthorized access n “Active” processing to take internal actions on data n Presentation and Visualization of data n Maintaining the database and associated programs over its lifetime Main Characteristics of the Database Approach (1) n Self-describing nature of a database system: n A DBMS catalog stores the description of a particular database n The description is called meta-data n This allows the DBMS software to be integrated with different database applications n Insulation between programs and data: n Allows changing data structures and data storage organization without having to change the DBMS access programs. n Accomplished through data abstraction n A data model is used to hide storage details and present the users with a conceptual view of the database. n Programs refer to the data model constructs rather than data storage details Called program-data independence. Main Characteristics of the Database Approach (2) n Support of multiple views of the data: n Each user may see a different view of the database, which describes only the data of interest to that user. n Sharing of data and multi-user transaction processing: n Allowing a set of user transactions to access and update the database concurrently (at the same time). n Concurrency control within the DBMS guarantees that each transaction is correctly executed or aborted n Recovery subsystem ensures each completed transaction has its effect permanently recorded in the database n OLTP (Online Transaction Processing) is a major part of database applications (allows hundreds of concurrent transactions to execute per second) Example of meta-date in a simplified database catalog Types of Database Users (Actors on the scene) n Database administrators: n Responsible for authorizing/controlling access to the database; coordinating and monitoring its use; acquiring software and hardware resources; and monitoring efficiency of operations. The DBA is accountable for security breaches and poor system response time. n Database Designers: n Responsible for defining database structure, constraints, and transactions; communicate with users to understand their needs. n End-users: Use the database for queries, reports, and updating the database content. Can be categorized into: n Casual end-users: access database occasionally when needed n Naïve (or Parametric) end-users: largest section of end-user population. n Use previously implemented and tested programs (called “canned transactions”) to access/update the database. Examples are bank-tellers or hotel reservation clerks or sales clerks. n Sophisticated end-users: n These include business analysts, scientists, engineers, etc. Many use tools of software packages that work closely with the stored database. n Stand-alone end-users: n Mostly maintain personal databases using ready-to-use packaged applications.  Types of Database Applications n Traditional Applications: n Numeric and Textual Databases in Business Applications n More Recent Applications: n Multimedia Databases (images, videos, voice, etc.) n Geographic Information Systems (GIS) n Data Warehouses n Real-time and Active Databases n Many other applications Advantages of Using the Database Approach n Controlling redundancy in data storage and in development and maintenance efforts. n Restricting unauthorized access to data. n Providing persistent storage for program Objects n Providing Storage Structures (e.g. indexes) for efficient Query Processing n Providing backup and recovery services. n Providing multiple interfaces to different classes of users. n Representing complex relationships among data. n Enforcing integrity constraints on the database. n Permitting inferencing and actions using rules and triggers n Allowing multiple “views” of the same data Additional Implications of Using the Database Approach n Potential for enforcing standards: n Crucial for the success of database applications in large organizations. Standards refer to data item names, display formats, screens, report structures, meta-data, etc. n Reduced application development time: n The time needed to add each new application is reduced. n Flexibility to change data storage structures: n Storage structures may evolve to improve performance, or because of new requirements. n Availability of up-to-date information: n Extremely important for on-line transaction systems such as airline, hotel, car reservations. n Economies of scale: n Wasteful overlap of resources and personnel can be avoided by consolidating data and applications across departments. Historical Development of Database Technology n Early Database Applications using Hierarchical and Network Systems: n Starting in the mid-1960s and continuing through the 1970s and 1980s. Were based on three main paradigms: hierarchical systems, network model–based systems, and inverted file systems. n Relational Model based Systems: n Relational model was introduced in 1970, and heavily researched and experimented with at IBM Research and several universities. Relational DBMS Products emerged in the early 1980s and now exist on almost all types of computers, from small personal computers to large servers. n Object-oriented and emerging applications: n Object Databases were introduced in late 1980s and early 1990s. Their use has not taken off much. Many relational DBMSs have incorporated object database concepts, leading to a new category called object-relational databases (ORDBs) n Extended relational systems add further capabilities (e.g. for multimedia data, XML, spatial, and other data types) n Data on the Web and E-commerce Applications: n Starting in the 1990s, e-commerce emerged as a major application on the Web. The critical information on e-commerce Web pages is dynamically extracted data from DBMSs, such as flight information, product prices, and product availability. n The eXtended Markup Language (XML) is one standard for interchanging data among various types of databases and Web pages. Extending Database Capabilities n New functionality is being added to DBMSs in the following areas: n Scientific Applications n XML (eXtensible Markup Language) n Image Storage and Management n Audio and Video Data Management n Data Warehousing and Data Mining n Spatial Data Management and Geographic Information Systems n Time Series and Historical Data Management n Collecting and fusing data from distributed sensors When not to use a DBMS n Main inhibitors (costs) of using a DBMS: n High initial investment and possible need for additional hardware. n Overhead for providing generality, security, concurrency control, recovery, and other functions. n When a DBMS may be unnecessary: n If the database and applications are simple, well defined, and not expected to change. n If there are stringent real-time requirements that may not be met because of DBMS overhead. n If access to data by multiple users is not required. n When no DBMS may suffice: n If the database system is not able to handle the complexity of data because of modeling limitations n If the database users need special operations not supported by the DBMS n When DBMS overhead makes it impossible to achieve the needed application performance Main Reference 1. Chapter 1: The Complete chapter (Fundamentals of Database Systems, Global Edition, 7th Edition (2017) by Ramez Elmasri & Shamkant Navathe) Additional References https://courses.cs.vt.edu/cs4604/Spring21/pdfs/1-intro.pdf https://courses.cs.vt.edu/cs4604/Spring21/pdfs/12-nosql.pdf This Presentation is mainly dependent on the textbook: Fundamentals of Database Systems, Global Edition, 7th Edition (2017) by Ramez Elmasri & Shamkant Navathe Thank You