Glossary

   

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Aggregate Function

A snippet of programming code that executes a particular type of mathematical aggregation on a set of data and returns a single value.

Aggregate View

A view used to display information produced by aggregating a particular set of data in a specific manner.

Alternate Key

A candidate key that has not been designated as a primary key.

Analytical Database

A type of database that stores static data and is used when there is a need to track trends, view statistical data over a long period of time, or make tactical or strategic business projections; it is typically associated with OLAP.

Application

A commercial or custom-built software program that is typically used to provide a user -friendly interface for a database.

Application Development

The process of designing and creating an application that will serve as the user interface for a database.

Application Program

Commercial or custom-built software that serves as the user-interface to a database.

Application Oriented Business Rule

A rule that imposes constraints that you must establish within the physical design of the database or within the design of the database application.

Artificial Candidate Key

A field created for the sole purpose of serving as a candidate key. It's existence is due to an absence of any "naturally occurring" candidate keys within the table.

Associative Table

See [Linking Table]

Attribute

The relational model's equivalent of a field.

Base Tables

Tables that form the basis of a view.

Business Rule Specification

Represents all of the characteristics of a business rule, such as the rule statement, the constraint it imposes, the structures it affects, and so on.

Business Rules

Restrictions or limitations on certain aspects of a database based on the ways an organization perceives and uses its data.

Calculated Field

A field that contains a concatenated text value or the result of a mathematical expression.

Calculated-Field List

A list of fields that can be defined only within an RDBMS. (Recall that you cannot define calculated fields within a table structure.)

Cardinality

The type of relationship that exists between a pair of tables in a relational database.

See also [Relationship]

Child Table

Within a given relationship, a table containing records that are explicitly dependent upon the existence of records in the related table.

Client/Server RDBMS

A type of RDBMS in which data resides on a computer acting as a database server and users interact with the data through applications residing on their own computer, known as the database client.

Closed Question

A question that has a definitive, finite set of answers. This type of question leaves little opening for further follow-up questions.

Command Prompt

A set of one or more symbols indicating the area within an operating system or command-driven software program in which a user can enter and execute commands. For example, C:\> is a command prompt within the MS-DOS operation system, and R> is the command prompt within R:BASE Technologies' R:BASE database software.

Composite Primary Key

A primary key composed of two or more fields.

Data

The values stored in the database.

Data Consistency

Every occurrence of a given field value throughout the entire database is exactly the same.

Data-Entry Form

A screen within an application program used to gather and collect data.

Data Integrity

A set of rules or guidelines that governs the validity, consistency, and accuracy of the data in a database. There are four types of data integrity: table-level, field-level, relationship-level , and business rules.

Data Structure

A particular construct used to store data, such as a field or table.

Data Table

A table that stores data used to supply information; it is the most common type of table in a relational database.

Data View

A view used to examine and manipulate data from one or more base tables.

Database Application Program

See [Application Program]

Database Developer

A person who designs and implements a database.

Database-Design Process

The set of actions required to design the logical structure of a database.

Database Oriented Business Rule

A rule that imposes constraints that you can establish within the logical design of the database.

DBMS (Database-Management System)

A software program that is used to create, maintain, modify, and manipulate a database.

Degree of Participation

Considering a given relationship between a pair of tables within a relational database, this is the minimum and maximum number of records that one table can have associated with a single record in the related table.

Deletion Rule

A rule that determines what the RDBMS should do when a user places a request to delete a given record in the parent table of a relationship.

Domain

See [Field Specification]

Domain Integrity

See [Field-Level Integrity]

Duplicate Data

A nonprimary key value that appears in more than one table within the database.

Duplicate Field

A field that appears in two or more tables for any of these reasons: It is used to relate a set of tables together; it indicates multiple occurrences of a particular type of value; or there is a perceived need for supplemental information.

Dynamic Data

Data that changes constantly and always reflects up-to-the-minute information.

Elements of a Candidate Key

This is a set of guidelines used to determine whether a given field is fit to serve as a candidate key.

Elements of a Foreign Key

This is a set of guidelines used to determine whether a given field is fit to serve as a foreign key.

Elements of a Primary Key

This is a set of guidelines used to determine whether a given candidate key field is fit to serve as a primary key.

Elements of the Ideal Field

A set of guidelines used to create sound field structures and to help identify poorly designed fields.

Elements of the Ideal Table

A set of guidelines used to create sound table structures and to help identify poorly designed tables.

End User

A person who uses and works with a database or database application program.

End-User Application

Commercial or custom-built software that serves as the user interface to a database.

Entity Integrity

See [Table-Level Integrity]

Event

Something that occurs at a given point in time (such as a doctor's appointment or stock transaction) that can be represented by a table.

Explicit Information

Information that is clearly stated within the response to a given question.

Extended Data Types

Additional data types provided by many RDBMS programs that go beyond those specified by the SQL Standard.

Field

The smallest structure in the database. It represents a characteristic of the subject of the table to which it belongs and is the only structure that actually stores data within the database.

Field Specification

Represents all of the general, physical, and logical elements of a field. (This is traditionally known as a domain.)

Field-Level Integrity

This type of data integrity warrants the following: the identity and purpose of a field is clear and all of the tables in which it appears are properly identified; field definitions are consistent throughout the database; the values of a field are consistent and valid; and the types of modifications, comparisons, and operations that can be applied to the values in the field are clearly identified.

Field Specific Business Rule

A rule that imposes constraints on the elements of a field specification for a given field.

Filter

A set of one or more constraints imposed on a view that causes it to return a specific set of information.

Final Table List

This list contains key information ( name , type, and description) on every table in the database.

First-Order Predicate Logic

One of the two branches of mathematics upon which the relational model is based.

Hierarchical Database

A database in which data is structured hierarchically and is typically diagrammed as an inverted tree.

Implementation Process

The set of actions required to take a logical database design and incorporate it within a specific RDBMS.

Implicit Information

Information that is not expressly stated within a response to a given question; you must derive it from your examination of the response.

Index

A structure within an RDBMS program that can be used to improve data processing.

Information

Data that is processed in a manner that makes it meaningful and useful to the person working with it or viewing it.

Information Requirements

Information that must be supported by the data in the database in order for the organization to function properly, effectively, and efficiently .

Inherited Database

See [Legacy Database]

Keys

Special fields that play very specific roles within a table; the type of key determines its purpose within the table. There are four significant types of key: candidate, primary, alternate, and foreign.

LAN

See [Local Area Network]

Legacy Database

A database that has been in existence and in use for several years or more.

Linking Table

A table that helps to establish a many-to-many relationship between a given pair of tables.

List of Characteristics

A collection of nouns that imply various attributes of the items on the List of Subjects.

List of Subjects

A collection of nouns that represent subjects that may be of interest to the organization.

Local Area Network ( LAN )

A group of computers and peripherals located within a relatively limited geographical area that share services and resources.

Logical Child Relationship

A relationship that exists between a given table in one hierarchical database and another table in a second hierarchical database.

Logical Data Independence

Changes made to the logical design of the database will not adversely affect the applications built upon the database.

Lookup Table

See [Validation Table]

Mainframe Computer

A large, high-end, extremely powerful computer designed to handle literally millions of highly intensive computations simultaneously .

Many-to-Many Relationship

A relationship between a pair of tables in a relational database in which a single record in the first table can be related to many records in the second table and a single record in the second table can be related to many records in the first table.

Member

The subordinate node in a given relationship within a network database.

Missing Value

A data value that has not been entered into a given field due to human error.

Mission Objective

A statement that represents a general task that a user will perform against the data in the database.

Mission Statement

A statement that establishes the purpose of the database and provides a distinct focus for your design work.

Multilevel Integrity

This incorporates two or more of the following: field-level integrity, table-level integrity, relationship-level integrity, and business rules.

Multipart Field

A field that contains more than one type of distinct value.

Multivalued Field

A field that contains multiple instances of the same type of value.

Network Database

A database in which data is structured hierarchically and is typically diagrammed as an inverted tree. Unlike the hierarchical database, however, it can contain several inverted trees that share branches.

Node

A given collection of records within a network database.

Non-key

A field that does not serve as a candidate, primary, alternate, or foreign key.

Normal Form

A specific set of rules that can be used to test a table structure to ensure that it is sound and free of problems.

Normalization

The process of decomposing large tables into smaller ones in order to eliminate redundant data and duplicate data.

Null

This represents a missing or unknown value; it does not represent a zero or a text string of one or more blank spaces.

Object

A tangible item (such as a person, place, or thing) that can be represented by a table.

OLAP (On-Line Analytical Processing)

A method of presenting data from an analytical database in which the data is summarized and presented in the form of a table or cube.

OLTP (On-Line Transaction Processing)

A system for processing transactions as soon as the computer receives them and updating master files immediately in a database-management system.

One-to-Many Relationship

A relationship between a pair of tables in a relational database in which a single record in the first table can be related to many records in the second table, but a single record in the second table can be related to only one record in the first table.

One-to-One Relationship

A relationship between a pair of tables in a relational database in which a single record in the first table is related to only one record in the second table, and a single record in the second table is related to only one record in the first table.

On-Line Analytical Processing

See [OLAP]

On-Line Transaction Processing

See [OLTP]

Open -Ended Question

A question that can be answered in a variety of ways and can lead to further follow-up questions.

Operating System

The complete set of software required to manage and provide services for the computer's hardware, peripheral equipment (such as printers and scanners ), and all other software programs. The computer cannot function without the operating system.

Operational Database

A type of database that stores dynamic data and is used in situations where there is a need to collect, modify, and maintain data on a daily basis; it is typically associated with OLTP.

Orphaned Record

Given two related tables, this is a record in one table that is not associated with any record in the other table.

Owner

The main node in a given relationship within a network database.

Owner/Member Relationship

A type of relationship in a network database in which an owner table can be associated with one or more member tables, but a single member table must be associated with a specific owner table.

Paper-Based Database

A loose collection of forms, index cards, manila folders, and so on, used to collect and maintain data.

Parent/Child Relationship

A type of relationship in a hierarchical database in which a parent table can be associated with one or more child tables, but a single child table can be associated with only one parent table.

Parent Table

Within a given relationship, a table containing records that are not dependent upon the existence of records in the related table.

Parse

To decompose a given data value into smaller, distinct parts .

Physical Data Independence

Changes the database software vendor makes to the physical implementation of the database will not adversely affect the applications built upon the database.

Pointer

A mechanism that explicitly links a parent table to a child table in a hierarchical database.

Preliminary Field List

A list of fields that represents the organization's fundamental data requirements and constitutes the core set of fields that must be defined in the database.

Preliminary Table List

The core set of tables that must be defined in the database.

Primary Key

A field or group of fields that uniquely identifies each record within a table.

Programming Environment

The combination of a given computing platform (PC, client/server, mainframe, etc.), operating system, and programming language.

Programming Language

A software program that can be used to define sets of instructions that will ultimately be processed and executed by the computer.

Query

A request for information posed to the database via an SQL query statement.

Query Builder

A tool within a database software program that allows a user to build a query via an easy-to-use graphical interface.

RDBMS (Relational Database Management System)

A software program that is used to create, maintain, modify, and manipulate a relational database.

Record

A structure that is composed of a complete set of singular values (regardless of whether any are null) for every field within a table and represents a unique instance of the table's subject.

Recursive Relationship

See [Self-Referencing Relationship]

Redundant Data

A value that is repeated in a field as a result of the field's participation in relating two tables or as a result of some field or table anomaly.

Reference Field

See [Duplicate Field]

Referential Integrity

See [Relationship-Level Integrity]

Relation

The relational model's equivalent of a table.

Relational Database

A type of database that stores data in relations (perceived by the user as tables). Each relation is composed of tuples (records) and attributes (fields).

Relational Database Management System

See [RDBMS]

Relational Model

A data model based on set theory and first-order predicate logic invented by Dr. Edgar F. Codd.

Relationship

An interdependence that exists between two tables when records in the first table can in some way be associated with records in the second table. There are three types of relationships in a relational database: one-to-one, one-to-many, and many-to-many.

Relationship Diagram

A graphic representation of the relationship between a given pair of tables or between a given set of records within a table.

Relationship-Level Integrity

A type of data integrity that ensures that the relationship between a pair of tables is sound and that the records in the tables are synchronized whenever data is entered into, updated in, or deleted from either table.

Relationship Specific Business Rule

A rule that imposes constraints that affect the characteristics of a relationship.

Report

Any hand-written , typed, or computer-generated document used to arrange and present data in such a way that it is meaningful to the person or people viewing it.

Root Table

The topmost table in a hierarchical database structure.

Screen Presentation

A series of screens that discuss various topics in an organized manner.

Self-Referencing Many-to-Many Relationship

A relationship that exists when a given record in a table can be related to one or more other records within the table and one or more records can themselves be related to the given record.

Self-Referencing One-to-Many Relationship

A relationship that exists when a given record in a table can be related to one or more other records within the table.

Self-Referencing One-to-One Relationship

A relationship that exists when a given record in a table can be related to only one other record within the table.

Self-Referencing Relationship

A relationship that exists between the records within a table. Similar to its dual-table counterpart , a self-referencing relationship can be one-to-one, one-to-many, or many-to-many.

Set Structure

A transparent construction that establishes and represents a relationship within a network database.

Set Theory

One of the two branches of mathematics upon which the relational model is based.

SQL (Structured Query Language)

A standardized language used to create, maintain, modify, and query relational databases.

Static Data

Data that is never (or very rarely) modified.

Structural Integrity

A set of rules or guidelines that governs the manner in which fields, tables, and views are defined.

Structured Query Language

See [SQL]

Subset Table

A table that represents a subordinate subject of a particular data table.

Table

The chief structure in a database. It is composed of fields and records and always represents a single, specific subject.

Table Description

A statement that provides a clear definition of the subject represented by the table and states why the subject is important to the organization.

Table-Level Integrity

This type of data integrity ensures that a table is free of duplicate records and that the values of the table's primary key are unique, never null, and exclusively identify the table records.

Tuple

The relational model's equivalent of a record.

Type of Participation

The manner in which a table participates within a given relationship in a relational database. The type of participation can be either mandatory or optional.

Type of Relationship

The manner in which a given pair of tables can be related (one-to-one, one-to-many, many-to-many).

Unknown Value

A value for a specific field that has yet to be determined or defined.

URL

An acronym for Uniform Resource Locator. It represents an address for a given resource on the Internet, such as http://www.ForMereMortals.com.

Validation Table

A table that stores data specifically used to implement data integrity. (This is also known as a lookup table.)

Validation View

A view used specifically to implement data integrity.

View

A virtual table composed of fields from one or more base tables in the database.

View Specification

Represents all of the characteristics of a view, such as the name, type, base tables, and so on.

WAN

See [Wide Area Network]

Web Page

A document consisting of a Hypertext Markup Language (HTML) file and associated support files that can be accessed via the Internet.

Wide Area Network ( WAN )

A group of computers and peripherals located over a widespread geographic area that depends on various communications devices to share services and resources.

Zero-Length String

Two consecutive single quotes with no space in between them.

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