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DBMS 1 | Introduction to DBMS
This document provides an introduction to database management systems, contrasting data and information, and defining key concepts such as databases, database management systems, and web-based information systems. It discusses the architectures of database systems, the roles of SQL, and important features of a DBMS including data consistency and security. Furthermore, it explores various data models, comparing SQL and NoSQL databases, as well as providing examples of relational and non-relational database systems.
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DBMS 1 | Introduction to DBMS
- 1. Database Management System Introduction MohammadImam Hossain, Lecturer, Dept. of CSE, UIU
- 2. Data vs Information ComputerData ▸ Data is a collection of values. Those values can be characters, numbers, or any other data type. ▸ Computer data is a bunch of 1’s and 0’s, known as binary data. ▸ Computer data is processed by the computer’s CPU and is stored digitally in files and folders on the computer’s hard disk. Example of Data: UIU, Email:, Mr. X, x@cse.uiu.ac.bd, Dept. of CSE, Lecturer 2 Mohammad Imam Hossain, Lecturer, Dept. of CSE, UIU Information ▸ When data are processed, interpreted, organized, structured or presented in a given context so as to make them meaningful or useful, they are called information. ▸ Data is raw material (i.e. bits of information) and Information is the product. Example of Information : Mr. X Lecturer Dept. of CSE UIU Email: x@cse.uiu.ac.bd
- 3. Data vs Information ComputerData ▸ Data is a collection of values. Those values can be characters, numbers, or any other data type. ▸ Computer data is a bunch of 1’s and 0’s, known as binary data. ▸ Computer data is processed by the computer’s CPU and is stored digitally in files and folders on the computer’s hard disk. Example of Data: UIU, Email:, Mr. X, x@cse.uiu.ac.bd, Dept. of CSE, Lecturer 3 Mohammad Imam Hossain, Lecturer, Dept. of CSE, UIU Information ▸ When data are processed, interpreted, organized, structured or presented in a given context so as to make them meaningful or useful, they are called information. ▸ Data is raw material(i.e. bits of information) and Information is the product. Example of Information : Mr. X Lecturer Dept. of CSE UIU Email: x@cse.uiu.ac.bd Data Data Data Processing Information
- 4. Web-based Information System Web-basedInformation System An information system that uses Internet web technologies to deliver information and services, to users or other information systems/applications. 4 Mohammad Imam Hossain, Lecturer, Dept. of CSE, UIU
- 5. Web-based Information System Web-basedInformation System An information system that uses Internet web technologies to deliver information and services, to users or other information systems/applications. 5 Mohammad Imam Hossain, Lecturer, Dept. of CSE, UIU What is happening in the background !!!!
- 6. Web-based System >>Background Process 6 Mohammad Imam Hossain, Lecturer, Dept. of CSE, UIU 192.168.0.103 192.168.0.115 192.168.0.110 157.240.0.35 HTTP req HTTP res DNS Recursor (Internal DNS Server) Database Server Database System SQL 172.210.0.25 8.8.8.8 Facebook
- 7. Web-based System >>Background Process 7 Mohammad Imam Hossain, Lecturer, Dept. of CSE, UIU 192.168.0.103 192.168.0.115 192.168.0.110 157.240.0.35 HTTP req HTTP res Database Server Database System SQL 172.210.0.25 8.8.8.8 Facebook Information Data DNS Recursor (Internal DNS Server)
- 8. 8 Mohammad Imam Hossain,Lecturer, Dept. of CSE, UIU Web-based System >> Two-tier vs Three-tier Architecture Two-tier Architecture The application resides at the client machine, and invokes database system functionality at the server machine through query language statements. Three-tier Architecture The client machine acts as a front end that communicates with an application server. The application server, in turn, communicates with a database system to access data. The business logic of the application, which says what actions to carry out under what conditions, is embedded in the application server, instead of being distributed across multiple clients.
- 9. DNS Recursor (Internal DNSServer) Database vs Database Management System 9 Mohammad Imam Hossain, Lecturer, Dept. of CSE, UIU 192.168.0.103 192.168.0.115 192.168.0.110 157.240.0.35 HTTP req HTTP res Database Server Database System = DBMS + Database SQL 172.210.0.25 8.8.8.8 Facebook Database A database is an organized collection of interrelated data, generally stored and accessed electronically from a computer system. Database Management System A DBMS is software that interacts with end users, applications, and the database itself to control the storage, organization, and retrieval of data.
- 10. DNS Recursor (Internal DNSServer) SQL – Structured Query Language 10 Mohammad Imam Hossain, Lecturer, Dept. of CSE, UIU 192.168.0.103 192.168.0.115 192.168.0.110 157.240.0.35 HTTP req HTTP res Database Server Database System = DBMS + Database SQL 172.210.0.25 8.8.8.8 Facebook Structured Query Language (SQL) - A special kind of programming language that is used for communicating with the database. - It is designed for managing data held in a relational database management system (RDBMS). - Types of SQL commands: ▪ DDL – Data Definition Language CREATE, DROP, ALTER, TRUNCATE ▪ DML – Data Manipulation Language INSERT, UPDATE, DELETE ▪ DQL – Data Query Language SELECT ▪ DCL – Data Control Language GRANT, REVOKE ▪ TCL – Transaction Control Language COMMIT, ROLLBACK, SAVEPOINT
- 11. Web-based System >>DBMS 11 Mohammad Imam Hossain, Lecturer, Dept. of CSE, UIU 192.168.0.103 192.168.0.115 192.168.0.110 157.240.0.35 HTTP req HTTP res SQL 172.210.0.25 8.8.8.8 Facebook PHP JSP(Java) ASP(C#) Ruby Django(Python) Node.js A DBMS understands the commands and the queries which define what data is required by the app or website and thus use the meaningful method of accessing the database to retrieve the information. Database Server Database System = DBMS + Database DNS Recursor (Internal DNS Server)
- 12. DBMS >> KeyFeatures 12 Mohammad Imam Hossain, Lecturer, Dept. of CSE, UIU 192.168.0.103 192.168.0.115 192.168.0.110 157.240.0.35 HTTP req HTTP res SQL 172.210.0.25 8.8.8.8 Facebook ▪ Minimizes data redundancy. ▪ Provides data consistency. ▪ Easy to write, update, search, delete data. ▪ Provides atomicity of updates. ▪ Concurrency control for multiple users. ▪ Provides data isolation. ▪ Provides high level of security. ▪ Easy to add/update different integrity constraints. Database Server Database System = DBMS + Database DNS Recursor (Internal DNS Server)
- 13. Database System Structure>> Query Processor 13 Mohammad Imam Hossain, Lecturer, Dept. of CSE, UIU Query Processor • DDL interpreter: interprets DDL statements and records the definitions in the data dictionary. • DML compiler: translates DML query statements into low-level instructions that the query evaluation engine understands. Also performs query optimization i.e. it picks lowest cost evaluation plan from a number of alternative evaluation plans. • Query evaluation engine: executes low-level instructions generated by the DML compiler. Program Query Tool Storage Manager Database Query Processor
- 14. Database System Structure>> Storage Manager 14 Mohammad Imam Hossain, Lecturer, Dept. of CSE, UIU Storage Manager • Authorization and integrity manager tests for the satisfaction of integrity constraints and checks the authority of users to access data. • Transaction manager ensures that the database remains in a consistent (correct) state despite system failures, and that concurrent transaction executions proceed without conflicting. • File manager manages the allocation of space on disk storage and the data structures used to represent information stored on disk. • Buffer manager is responsible for fetching data from disk storage into main memory, and deciding what data to cache in main memory. Program Query Tool Query Processor Storage Manager Database
- 15. Database System Structure>> Database 15 Mohammad Imam Hossain, Lecturer, Dept. of CSE, UIU Database • Data files, which store the database itself. • Data dictionary, which stores metadata about the structure of the database, in particular the schema of the database. • Indices, which provide fast access to data items. A database index provides pointers to those data items that hold a particular value. Program Query Tool Query Processor Storage Manager Database
- 16. Data Abstraction 16 Mohammad ImamHossain, Lecturer, Dept. of CSE, UIU ▪ A database system is a collection of interrelated data(DB) and a set of programs (DBMS) that allow users to access and modify these data. ▪ A major purpose of a database system is to provide users with an abstract view of the data. That is, the system hides certain details of how the data are stored and maintained. ▪ To simplify users’ interactions with the system, developers hide the complexity from users through several levels of data abstraction.
- 17. Database Schema ▸ Schemadescribes the overall design of the database at different levels. ▸ Each schema (logical) corresponds to a data model that is a collection of conceptual tools and languages for describing data, data relationships, data semantics, and consistency constraints. 17 Physical schema Logical schema External/View schema Mohammad Imam Hossain, Lecturer, Dept. of CSE, UIU
- 18. Types of DataModels ▸ High-level conceptual data model ▪ E-R Model ▪ Object oriented Model ▸ Record based logical data models - These models specify logical structure of database with records, fields and attributes. ▪ Relational Model – collections of tables ▪ Hierarchical Model – collections of trees ▪ Network Model – collections of records and links (graphs) ▸ Physical data models (physical level) 18 Mohammad Imam Hossain, Lecturer, Dept. of CSE, UIU
- 19. SQL vs NoSQLDatabase 19 Mohammad Imam Hossain, Lecturer, Dept. of CSE, UIU SQL NoSQL Relational Database Non-relational Database SQL databases use structured query language and have a predefined schema. NoSQL databases have dynamic schemas for unstructured data. SQL databases are vertically scalable. NoSQL databases are horizontally scalable. SQL databases are table based. NoSQL databases are document, key-value, graph or wide- column stores. • SQLite • PostgreSQL • Oracle • MySQL • Microsoft SQL server • MongoDB • Cassandra
- 20. Relational DBMS >>MySQL 20 Mohammad Imam Hossain, Lecturer, Dept. of CSE, UIU Student student_id name age 1 ABC 25 2 DEF 20 3 GHI 22 4 JKL 27 Course course_id name faculty 1 Java X 2 Python Y 3 CPP W 4 JS M Student_Course student_id course_Id marks 1 4 85 1 3 90 2 3 70 4 2 67
- 21. Non-relational DBMS >>MongoDB 21 Mohammad Imam Hossain, Lecturer, Dept. of CSE, UIU Collection 1 Collection 2
- 22. 22 THANKS! Any questions? Email :imam@cse.uiu.ac.bd Reference: Database System Concepts by S. Sudarshan, Henry F. Korth, Abraham Silberschatz