DATABASE SYSTEMS (phần 2) doc

... databases and Web pages. XML combines concepts from the models used in document systems with database modeling concepts. 1.7.5 Extending Database Capabilities for New Applications The success of database systems in traditional applications ... processing and optimization, their performance improved. Eventually, relational databases became the dominant type of database systems fo...

Ngày tải lên: 07/07/2014, 06:20

Ngày tải lên: 26/01/2014, 17:20

... success of rela- tional databases in the commercial world. Because it became a standard for relational databases, users were less concerned about migrating their database applications from other types of database systems- for example, network or ... being proposed as a means of querying databases; conferences such as the Visual Database Systems Workshop (e.g., Arisawa and Catarci (20...

Ngày tải lên: 07/07/2014, 06:20

... 2, SQL_FLOAT, &salary, 4, &fetchlen2) ; 17) ret2 = SQLFetch(stmt1) ; 18) while (! ret2) { 19) printf(lname, salary) 20) ret2 = SQLFetch(stmtl) ; 21) } 22) } 23) } FIGURE 9.12 Program segment ... a constraint between two sets of attributes from the database. Suppose that our relational database schema has n attributes AI' A 2 , ••• , An; let us think of the whole database...

Ngày tải lên: 07/07/2014, 06:20

... Context for Using Database Systems Database systems have become a part of the information systems of many organizations. In the 1960s information systems were dominated by file systems, but since ... THE DATABASE DESIGN AND IMPLEMENTATION PROCESS We now focus on activities 2 and 3 of the database application system life cycle, which are database design and implementation. T...

Ngày tải lên: 07/07/2014, 06:20

... correspond to the DDL (Data Definition Language) of the database system (see Chapter 2). 20.1 Overview of Object-Oriented Concepts I 641 oriented database systems. Section 20.2 discusses object identity, object structure, and type constructors. Section 20.3 ... Object Databases 20.4 TYPE AND CLASS HIERARCHIES AND INHERITANCE Another main characteristic of 00 database systems is th...

Ngày tải lên: 07/07/2014, 06:20

... relational database and an object database? 21.12. Describe the steps of the algorithm for object database design by EER-to-OO mapping. Exercises 21.13. Design an 00 schema for a database application that you ... discuss the concept of a database. Because a ODBMS can create many different databases, each with its own schema, the ODMG object model has interfaces for DatabaseFactory an...

Ngày tải lên: 07/07/2014, 06:20

... object. For manipulation of doc objects, functions such as the following are used: Import _doc (doc, text) returns doc. Export _doc (doc, text) returns text. Assign (doc) returns doc. Destroy (doc) returns void. The Assign and Destroy functions ... operation. Database audits are particularly important for sensitive databases thar are updated by many transactions and users, suc...

Ngày tải lên: 07/07/2014, 06:20

... only retrieve from the database; updating with new information is limited to database domain experts who supervise and analyze the new data being entered. 29.1 MOBILE DATABASES 1 Recent advances ... of the software problems-which may involve data management, transaction management, and database recovery-have their origins in distributed database systems. In mobile computing, however,...

Ngày tải lên: 07/07/2014, 06:20

... typically involving mobile database systems. These include server database design for server databases, consistency and synchronization management among client and server databases, transaction and ... http://www.ncbLnlm.nih.gov/genome/seq/. The MITOMAP database developed in Kogelnik (1998) can be accessed at http://www.mitomap.org/. The biggest protein database SWISS-PROT can be acc...

Ngày tải lên: 07/07/2014, 06:20