Database Chapter 1

Entity

A person, place, an object, an event, or a concept in the user environment about which the organization wishes to maintain data.

Project

A planned undertaking of related activities to reach an objective that has a beginning and an end.

Constraint

A rule that cannot be violated by database users.

Enterprise resource planning (ERP)

A business management system that integrates all functions of the enterprise, such as manufacturing, sales, finance, marketing, inventory, accounting, and human resources. ERP systems are software applications that provide the data necessary for the enterprise to examine and manage its activities.

Repository

A centralized knowledge base for all data definitions, data relationships, screen and report formats, and other system components. A repository contains an extended set of metadata important for managing databases as well as other components of an information system.

Database

A database is an organized collection of logically related data, usually designed to meet the information needs of multiple users in an organization. It is important to distinguish between the database and the repository. The repository contains definitions of data, whereas the database contains occurrences of data.

Rational Database

A database that represents data as a collection of tables in which all data relationships are represented by common values in related tables.

Conceptual schema

A detailed, technology independent specification of the overall structure of organizational data.

User view

A logical description of some portion of the database that is required by a user to perform some task.

Database management system

A software system that is used to create, maintain, and provide controlled access to user databases.

DBMS

A software system used to create, maintain, and provide controlled access to user databases.

Data

A stored representation of objects and events that have meaning and importance in the user's environment.

Database Application

An application program (or set of related programs) that is used to perform a series of database activities (create, update, read, and delete) on the users behalf.

Agile software development

An approach to database and software development that emphasizes "individuals and interactions over processes and tools, working software over comprehensive documentation, customer collaboration over contract negotiation, and response to change over following a plan.

Data warehouse

An integrated decision support database whose content is derived from the various operational databases.

Internal schema

An internal schema today really consists of two separate schemas: a logical schema and a physical schema. The logical schema is the representations of data for a type of data management technology. The physical schema describes how data are to be represented and stored in secondary storage using a particular DBMS.

Prototyping

An iterative process of systems development in which requirements are converted to a working system that is continually revised through close work between analysts and users.

Database

An organized collection of logically related data.

Computer Aided Software Engineering (CASE) tools

Automated tools used to design databases and application programs. Theses tools help with creation of data models and in some cases can also help automatically generate the "code" needed to create the database. We reference the use of automated tools for database design and development.

Application Program

Computer-based application programs are used to create and maintain the database and provide information to users.

Information

Data presented in a way in which the users knowledge has increased.

Metadata

Data that describe the properties or characteristics of end-user data and the context of those data.

Data and database administration

Database administrators are the people who are responsible for the overall management of data resources in an organization. Database administrators are responsible for physical database design and for managing technical issues in the database environment.

End Users

End users are persons throughout the organization who add, delete, and modify data in the database and who request or receive information from it.

Physical schema

Specifications for how data from a logical schema are stored in a computer's secondary memory by a database management system.

System Developers

System developers are people like systems analysts and programmers who design new application programs. System developers often use CASE tools for system requirements analysis and program design.

Enterprise Data modeling

The first step in database development, in which the scope and general contents of organizational databases are specified.

Data model

The graphical systems used to capture the nature and relationships among data.

Logical schema

The representation of a database for a particular data management technology.

Data independence

The separation of data descriptions from the application programs that use the data.

Systems Development Life Cycle (SDLC)

The traditional methodology used to develop, maintain, and replace information systems.

User Interface

The user interface includes languages, menus, and other facilities by which users interact with various systems components, such as CASE tools, application programs, the DBMS, and the repository.

External schema

This is the view of managers and other employees who are database users.

Conceptual schema

This schema combines the different external views into a singe, coherent and comprehensive definitions of the enterprise's data. The conceptual schema represents the view of the data architect or data administrator.