数据库系统原理(英文)-1-10文库帮手网 www.365xueyuan.com 免费帮下载 百度文库积分 资料 本文由zhaoxinyuelily贡献 ppt文档可能在WAP端浏览体验不佳。建议您优先选择TXT，或下载源文件到本机查看。 Chapter 1 Introduction Main Parts in This Chapter Database System Applications Purpose of Database Systems View of Data Database Languages Relational Database Database Design Data Storage and Querying Transaction Management Database Architectures Database Users and Administrators History of Database Systems Appendix: Data, Information, Knowledge, etc. February 2010 Database System Concepts- Chapter1 Introduction 2 1.0 DB, DBMS, DBS Definitions in the textbook Database (DB) a collection of interrelated data, stored in systems as files Database management system (DBMS) DB, or a collection of interrelated data set of programs to access the data in DB Database system (DBS) having the same definition as DBMS in the textbook the term DBS and DBMS are used interchangeably in the textbook February 2010 Database System Concepts- Chapter1 Introduction 3 1.0 DB, DBMS, DBS(cont.) DBMS provides an environment that is both convenient and efficient for store and retrieve information definition of structures for storage of information data manipulation mechanisms data safety mechanisms Definitions in some other textbooks Fig. 1.0.1 Database(DB) a collection of interrelated data , stored in systems as files February 2010 Database System Concepts- Chapter1 Introduction 4 1.0 DB, DBMS, DBS(cont.) Definitions in some other textbooks (cont.) Database management system (DBMS) a system/mechanism to manage data in DB or: set of programs to access the data in DB Database system(DBS) DB + DBMS + Users/Administers Database application system DB + DBMS + Application programs + Users/Administers February 2010 Database System Concepts- Chapter1 Introduction - 5 Application program 1 Application program 1 API, e.g.ODBC, JDBC DB file DBMS Users DB query language e.g. SQL DBMS DBS/DBAS Fig.1.0.1 DBS and DBAS DB 1.2 Purpose of Database Systems Databases and DBS touch all aspects of our lives Banking: all transactions Airlines: reservations, schedules Universities: registration, grades Sales: customers, products, purchases Manufacturing: production, inventory, orders, supply chain Human resources: employee records, salaries, tax deductions February 2010 Database System Concepts- Chapter1 Introduction - 7 1.2 Purpose of Database Systems (cont.) In the early days, data management applications were built on top of file systems E.g. Saving-bank enterprise a number of application programs to access data files A program to debit debit（将.记入借方） or credit （将.记 . . 入贷方） an account(帐户） A program to add a new account A program to find the balance（收付差额，余额） of an account A program to generate monthly statements February 2010 Database System Concepts- Chapter1 Introduction - 8 1.2 Purpose of Database Systems (cont.) Data management on the basis of file systems Example customer_record= in Customer_File FS access needs file name, item name, length of record, length of item , position of item in the record, storage structure, access method, . Demerit application programs are not independent of the file system ( or operating system) dependency among application programs and data (程序与 数据的非独立/依存性） February 2010 Database System Concepts- Chapter1 Introduction 9 Fig. 1.0.2 Why DBS needed direct access through disk controller access through OS file system access programs (II) access programs (I) access through data base system (DBS) (III) (II) access programs (III) (I) DBS API DBMS: relational tables logical structures and access methods system calls related to file management file system: files logical structures and access methods I/O system : drivers memory controllers (i.e. disk controller), on the basis of secondary storages physical structures, such as storage structures, access method secondary storage (e.g. disk, tape) and data on it (address: cylinder, track, sector) DB user view of data model DBMS view of file OS: Logical file Logical address : #Record Record1 DB files Physical File on disk Physical address： platter/track /sector DBS logical structures: Select Name From Student Where S#=100 relations/ tuples Recordk Recordi Recordm Fig. 1.0.3 Database access block1 block block1 blocki Block n blockk OS：file system and I/O subsystem 1.2 Purpose of Database Systems (cont.) Drawbacks of using file systems to store data data redundancy（冗余） and inconsistency（不一致性） multiple file formats, duplication（副本） of information in different files difficulty in data access need to write a new progra