DATABASE SYSTEMS (phần 4) pot

... concepts (see Chapter 24). • KR schemes include reasoning mechanisms that deduce additional facts from the facts stored in a database. Hence, whereas most current database systems are limited to ... relational database and a rela- tional database schema. A relational database schema S is a set of relation schemas S = (R I , R z , , R m } and a set of integrity constraints IC....

Ngày tải lên: 07/07/2014, 06:20

... discussing the role of information systems in organizations; database systems are looked upon as a part of information systems in large-scale applica- tions. We discussed how databases fit within an information ... discuss the role ofdata dictionaries in database design. Rozen and Shasha (1991) and Carlis and March (19 84) present different models for the problem of physical datab...

Ngày tải lên: 07/07/2014, 06:20

... (see Chapter 6). Practical Database Design and Tuning In this chapter, we first discuss the issues that arise in physical database design in Section 16.1. Then, we discuss how to improve database performance through database tuning in Section ... all phases of database design and point out the role of data dictionaries. Rozen and Shasha (1991) and Carlis and March (19 84) present d...

Ngày tải lên: 07/07/2014, 06:20

... in a database. Because part of the theoretical foundation for some deductive database systems is mathematical logic, such rules are often referred to as logic databases. Other types of systems, ... in the application programs that access the database. Section 24.3 will give a brief overview of spatial and multimedia databases. Spatial databases provide concepts for databases that kee...

Ngày tải lên: 07/07/2014, 06:20

... types of distributed database systems, including federated and multidatabase systems and highlights the problems of heterogeneity and the needs of autonomy in federated database systems, which will ... retrieve the employee 25.7 Distributed Databases in Oracle I831 Net8 Database server Database server Net8 (c:::>c:::>c:::> = EMPtable t- , , Sales , database CONNECT T...

Ngày tải lên: 07/07/2014, 06:20

... 262 sequence interaction, 263-264 database programming languages, 255 database schema, 27-28, 115 database servers, 36, 263 database state, 28 database systems active, 19 active database technology, 3 characteristics, 8-11 deductive, ... data, 902 database administrators (DBA), 12 interfaces for, 34 security and, 734 database applications, 49, 52-53, 255, 262 database desi...

Ngày tải lên: 07/07/2014, 06:20

Ngày tải lên: 23/02/2014, 19:20

... – SƯ ĐOÀN 2 – QUÂN ĐOÀN HẢI QUÂN 1 CHUYÊN ĐỀ HÀM SỐ VÀ ĐỒ THỊ BÀI TẬP HÀM SỐ BẬC HAI (PHẦN 4) Bài 1. Cho hàm số 2 2 3 y x x    (P). 1. Xác định tọa độ đỉnh; trục đối xứng và hướng

Ngày tải lên: 26/02/2014, 13:20