1. Ch. 1 데이터베이스시스템

2. Ch.1 Database System 데이터베이스시스템 2 What to Learn Database System Overview Entity-Relationship diagram Relational Data Model  Structure & Constraints  SQL language How to use Commercial DBMS’s  MS Access  MS SQL Server Normalization ( 정규화 ) Transaction & Concurrency ( 동시성 )

3. Ch.1 Database System 데이터베이스시스템 3 What to Learn Database and Database system Modeling a real world  Conceptual Modeling  Data Modeling  Data Structuring File processing system Advantages of database system

4. Ch.1 Database System 데이터베이스시스템 4 What is a database (1) data numbers, characters, images or other outputs from devices to convert physical quantities into symbols, in a very broad sense 현실세계의 사물과 사건을 문자, 수치, 기호, 음성, 그림 등의 형태로 표현한 기록 (record) information the result of processing, manipulating and organizing data in a way that adds to the knowledge of the person receiving it. 사용자에게 전달되어 의사결정 등에 유용하게 쓰이도록 가치 있는 형태로 변환된 뜻 (meaning, interpretation) Information = Processing (Data)

5. Ch.1 Database System 데이터베이스시스템 5 What is a database (2) database a collection of persistent data that is used by the application systems of some given enterprise 체계적으로 저장되고 통합적으로 관리되는 데이터의 집 합 (collection) Textbook definition (p.13) 조직체의 응용시스템들이 공유해서 사용하는 운영데이 터 (operational data) 들이 구조적으로 통합된 모임 (operational data means data from day-to-day operations. In these days we store all the necessary data in the database including decision support database, not just operational data)

6. Ch.1 Database System 데이터베이스시스템 6 Database system computerized record–keeping system a computerized system whose overall purpose is to store information and to allow users to retrieve and update that information on demand. 데이터베이스 개념과 기술에 입각하여 데이터를 수집 / 저 장 / 가공 / 제공하는 컴퓨터 응용시스템 Database Management System (DBMS) A component of a database system Software that handles all access to the database

7. Ch.1 Database System 데이터베이스시스템 7 Database system Information Database Computer DBMS Processing Users

8. Ch.1 Database System 데이터베이스시스템 8 logical schema data modeling Real World system boundary E-R diagram conceptual modeling physical schema data structuring conceptual world computer world stored database Modeling of the Real World

9. Ch.1 Database System 데이터베이스시스템 9 Conceptual modeling System boundary only the data we are interested in Entity any distinguishable object that is to be represented in the database e.g. book, student, department Relationship an association among entities

10. Ch.1 Database System 데이터베이스시스템 10 E-R diagram Attributes (properties 속성 ) Items we describe (express) entities or relationships with From the view of a database, entities and relationships are the same both of them are represented as tables BookStudentPublisher Seller Department publish purchase loan belong author ISBN loan date return date title purchase date

11. Ch.1 Database System 데이터베이스시스템 11 Data Modeling Data model an abstract, self-contained, logical definition of the objects, operators, constraints, and so forth, that together constitute the abstract machine 가상의 컴퓨터에서 데이터 객체들 의 구조, 연산, 제약조건들을 명시 한 정의 Data models differ in structure, operators, constraints

12. Ch.1 Database System 데이터베이스시스템 12 hierarchical data model (p.35) pre-relational, tree-structure, use pointers a node has only one parent node What if an employee works for two projects 회사 부서 1 프로젝트 1 프로젝트 2 프로젝트 3 사원 1 사원 5 사원 2 사원 3 사원 4

13. Ch.1 Database System 데이터베이스시스템 13 network data model (p.36) pre-relational, use pointers a node can have more than one parent node 대학 학과 1 학과 2 과목 1 과목 2 과목 3 학생 1 학생 5 학생 2 학생 3 학생 4

14. Ch.1 Database System 데이터베이스시스템 14 relational data model The data is perceived by the user as tables (and nothing but tables) 데이터베이스의 논리적 구조가 relation 즉, 테이블의 집합으로 표현 되는 데이터 모델 relation is a mathematical term for a table NAMEST_NOADDRESSDEPTGRADE 송치윤 52015 사당동컴퓨터 3.3 김구완 53116 홍제동정보통신 3.1 최재석 56034 양재동정보관리 3.5 조미림 52042 역삼동컴퓨터 2.9 Student table

15. Ch.1 Database System 데이터베이스시스템 15 Other data model Object-oriented data model from the OOP (object oriented programming) use pointers Object/Relational data model hybrid of OODB & RDB

16. Ch.1 Database System 데이터베이스시스템 16 Data Structuring Physical representation of data Consider file structure indexing

17. Ch.1 Database System 데이터베이스시스템 17 file processing system vs. database system What is file processing system Which is easier to use? Problems of file processing system 1. data incompatiblity 2. data redundancy 3. data dependency

18. Ch.1 Database System 데이터베이스시스템 18 example of problems Product1 (Prod_No, Prod_Name, price, monthlysales) Product2 (Prod_No, Prod_Name, cost, monthlyproduction) Product1 is sorted by Prod_No, while Product2 is sorted by Prod_Name Sales department & production department use different names for the same product. Prod_Name’s are used twice If the cost is inserted in Product1, application program that used Product1 should be changed.

19. Ch.1 Database System 데이터베이스시스템 19 Data in the database system Shared by multi-users Integrated in a single database Above characteristic requires  Standardization ( 표준화 )  Concurrency control ( 동시성 제어 )  Integrity ( 무결성 )  Security ( 보안성 )

20. Ch.1 Database System 데이터베이스시스템 20 Advantages of database systems The data can be shared Redundancy and Incompatibility can be reduced Transaction support can be provided (Transaction Commit or Rollback) Integrity can be maintained Security can be enforced Standards can be enforced Conflicting requirements can be balanced