cơ sở dữ liệu lê thị bảo thu chương ter 01 database system concepts and architecture [sinhvienzone.com]

Chapter 1: Database System Concepts and Architecture Jan - 2015 SinhVienZone.com https://fb.com/sinhvienzonevn Outline  File-based Approach and Database Approach  Three-Schema Architecture and Data Independence  Database Languages  Data Models, Database Schema, Database State  Data Management Systems Framework Jan - 2015 SinhVienZone.com https://fb.com/sinhvienzonevn Outline  File-based Approach and Database Approach  Three-Schema Architecture and Data Independence  Database Languages  Data Models, Database Schema, Database State  Data Management Systems Framework Jan - 2015 SinhVienZone.com https://fb.com/sinhvienzonevn File-based Approach   Data is stored in one or more separate computer files Data is then processed by computer programs - applications Jan - 2015 SinhVienZone.com https://fb.com/sinhvienzonevn File-based Approach Jan - 2015 SinhVienZone.com https://fb.com/sinhvienzonevn File-based Approach  Problems/Limitations    Jan - 2015 Data Redundancy Trang thai du thua Data Inconsistency Trai nguoc More details: see [2] SinhVienZone.com https://fb.com/sinhvienzonevn File-based Approach Jan - 2015 SinhVienZone.com https://fb.com/sinhvienzonevn File-based Approach  Shared File Approach  Data (files) is shared between different applications  Data redundancy problem is alleviated giam nhe Data inconsistency problem across different versions of the same file is solved  Jan - 2015 SinhVienZone.com https://fb.com/sinhvienzonevn File-based Approach  Shared File Approach  Other problems: cung nhac, Rigid data structure: If applications have to share khong lih dongfiles, the file structure that suits one application   Dong thoi Jan - 2015 might not suit another Physical data dependency: If the structure of the data file needs to be changed in some way, this alteration will need to be reflected in all application programs that use that data file No support of concurrency control: While a data file is being processed by one application, the file will not be available for other applications or for ad hoc queries SinhVienZone.com https://fb.com/sinhvienzonevn Files Files Customer File Applications Applications Customer Orders Customer File Stock File Order File Customer Orders Stock File Customer File Customer Invoicing Stock File Customer Invoicing Order File Order File Stock File Purchase Orders Supplier File Supplier File Stock File Stock Control Order File Jan - 2015 Purchase Orders SinhVienZone.com Stock Control Shared file approach https://fb.com/sinhvienzonevn 10 ... Approach and Database Approach  Three-Schema Architecture and Data Independence  Database Languages  Data Models, Database Schema, Database State  Data Management Systems Framework Jan - 2015 ... Approach and Database Approach  Three-Schema Architecture and Data Independence  Database Languages  Data Models, Database Schema, Database State  Data Management Systems Framework Jan - 2015 ... manipulating, and sharing databases among various users and applications (or a software system that enables users to define, create, maintain, and control access to the database) Jan - 2015 SinhVienZone.com