Chapter 1 Database System Concepts 6 th Ed

Chapter 1: 개요 Database System Concepts, 6 th Ed. ©Silberschatz, Korth and Sudarshan See www. db-book. com for conditions on re-use

데이터베이스 관리 시스템 (DBMS) n DBMS는 특정 분야 관련 정보를 저장/관리한다 l 상호 관련 있는 데이터의 모임 l 데이터를 액세스하기 위한 프로그램의 집합 l 사용하기 편하고 효율적인 환경을 제공 n Database 응용분야: l Banking: transactions l Airlines: reservations, schedules l Universities: registration, grades l Sales: customers, products, purchases l Online retailers: order tracking, customized recommendations l Manufacturing: production, inventory, orders, supply chain l Human resources: employee records, salaries, tax deductions n 데이터베이스는 일반적으로 그 크기가 매우 크다고 가정한다. Database System Concepts - 6 th Edition 1. 2 ©Silberschatz, Korth and Sudarshan

데이터 모델 n 아래 사항을 기술하는 도구들의 모임 Data l Data 관련성(relationships) l Data 의미(semantics) l Data 제약조건(constraints) l n 릴레이션 모델 (Relational model) n E-R 모델 (Entity-Relationship data model): DB 설계에 사용됨 n 객체기반 모델 (Object-based data models, Object-oriented and Object-relational) n Semistructured data model (XML) n 기타 : l l 네트워크 모델 (Network model) 계층 모델 (Hierarchical model) Database System Concepts - 6 th Edition 1. 8 ©Silberschatz, Korth and Sudarshan

릴레이션 모델 n Relational model (Chapter 2) n Example of tabular data in the relational model Columns Rows Database System Concepts - 6 th Edition 1. 9 ©Silberschatz, Korth and Sudarshan

A Sample Relational Database System Concepts - 6 th Edition 1. 10 ©Silberschatz, Korth and Sudarshan

데이터 정의어 (Data Definition Language, DDL) n DB 스키마를 정의하기 위한 명세 표기 l Example: create table instructor ( ID char(5), name varchar(20), dept_name varchar(20), salary numeric(8, 2)) n DDL 컴파일러는 데이터 사전 (data dictionary) 에 저장되는 테이블의 집합을 생성 n 데이터 사전에는 메타 데이터가 저장된다 (즉, 데이터에 관한 데이터) l Database schema l Integrity constraints 4 Primary key (ID uniquely identifies instructors) 4 Referential integrity (references constraint in SQL) – e. g. dept_name value in any instructor tuple must appear in department relation l Authorization Database System Concepts - 6 th Edition 1. 12 ©Silberschatz, Korth and Sudarshan

SQL n SQL: widely used non-procedural language Example: Find the name of the instructor with ID 22222 select name from instructor where instructor. ID = ‘ 22222’ l Example: Find the ID and building of instructors in the Physics dept. select instructor. ID, department. building from instructor, department where instructor. dept_name = department. dept_name and department. dept_name = ‘Physics’ l n 응용 프로그램은 다음 중 하나의 방법을 이용하여 DB에 액세스한다 Language extensions to allow embedded SQL l Application program interface (e. g. , ODBC/JDBC) which allow SQL queries to be sent to a database n Chapters 3, 4 and 5 l Database System Concepts - 6 th Edition 1. 13 ©Silberschatz, Korth and Sudarshan

Database Design? n Is there any problem with this design? Database System Concepts - 6 th Edition 1. 15 ©Silberschatz, Korth and Sudarshan

Design Approaches n 정규화 이론 (Chapter 8) l Formalize what designs are bad, and test for them n E-R 모델 (Chapter 7) l Models an enterprise as a collection of entities and relationships 4 Entity: a “thing” or “object” in the enterprise that is distinguishable from other objects – Described by a set of attributes 4 Relationship: l an association among several entities Represented diagrammatically by an entity-relationship diagram: Database System Concepts - 6 th Edition 1. 16 ©Silberschatz, Korth and Sudarshan

개체-관계 ( Entity-Relationship, E-R) 모델 n 개체와 관계를 이용하여 데이터베이스를 모델링 한다. l 개체 (Entity): a “thing” or “object” in the enterprise that is distinguishable from other objects 4 속성 l 집합에 의하여 표현된다. 관계 (Relationship): an association among several entities n E-R 다이어그램으로 표현할 수 있다: Database System Concepts - 6 th Edition 1. 17 ©Silberschatz, Korth and Sudarshan

질의 처리 (Query Processing) 1. Parsing and translation 2. Optimization 3. Evaluation Database System Concepts - 6 th Edition 1. 19 ©Silberschatz, Korth and Sudarshan

Database System Internals Database System Concepts - 6 th Edition 1. 22 ©Silberschatz, Korth

History of Database Systems n 1950 s and early 1960 s: l Data processing using magnetic tapes for storage 4 Tapes l provided only sequential access Punched cards for input n Late 1960 s and 1970 s: l Hard disks allowed direct access to data l Network and hierarchical data models in widespread use l Ted Codd defines the relational data model 4 Would 4 IBM 4 UC l win the ACM Turing Award for this work Research begins System R prototype Berkeley begins Ingres prototype High-performance (for the era) transaction processing Database System Concepts - 6 th Edition 1. 23 ©Silberschatz, Korth and Sudarshan

History (cont. ) n 1980 s: Research relational prototypes evolve into commercial systems 4 SQL becomes industrial standard l Parallel and distributed database systems l Object-oriented database systems n 1990 s: l Large decision support and data-mining applications l Large multi-terabyte data warehouses l Emergence of Web commerce l n Early 2000 s: XML and XQuery standards l Automated database administration n Later 2000 s: l Giant data storage systems 4 Google Big. Table, Yahoo PNuts, Amazon, . . l Database System Concepts - 6 th Edition 1. 24 ©Silberschatz, Korth and Sudarshan