Database Systems 8Ed, Chapt 2

Front 1

data model

Back 1

simple representation of real world data structures. graphical usually.

Front 2

attribute

Back 2

is a characteristic of an entity. fields are attributes

Front 3

entity

Back 3

any to be stored, person place thing or event

Front 4

relationship

Back 4

how entities relate to each other. an agent can serve many customers.

Front 5

business rule

Back 5

a brief and concise description of a policy principle or procedure

Front 6

constraint

Back 6

a restriction placed on data. each class can have only one teacher

Front 7

many to many

Back 7

M:N or *..* a student can take many classes and classes have many students

Front 8

one to many

Back 8

1:M or 1..* a painter paints many pictures but pictures have only one painter

Front 9

one to one

Back 9

a store has one manager and each manager has one store

Front 10

hierarchical model

Back 10

data model with an upside down tree. 1:M lacks structural independence

Front 11

segment

Back 11

a hierarchical models equivalent of a record type. root segment, child segment, etc

Front 12

data definition language

Back 12

refers to the network model. allows for the defining of data structures

Front 13

data management language

Back 13

refers to the network model. defines the environment in which data can be managed

Front 14

DBTG

Back 14

database task group. created in the 60's to set standards and methods

Front 15

schema

Back 15

the organization of the entire database, database name, the record type, and the components

Front 16

RDBMS

Back 16

relational database management system

Front 17

relation

Back 17

a table made up of rows and columns, each column represents an attribute

Front 18

tuple

Back 18

a row

Front 19

relational diagram

Back 19

shows how a databases entities relate to each other. 1:M, M:M etc

Front 20

chen notation

Back 20

uses boxes to diagram entities and their relationships, 1:M. Uses diamonds to show the verb, paints, teaches, etc

Front 21

connectivity

Back 21

refers to the entity relationship model. the relationship type. a painter PAINTS many paintings

Front 22

crow's foot notation

Back 22

replaces chen. refers to how the many symbol looks like a foot.

Front 23

entity instance

Back 23

refers to the entity model. a row in a relational table

Front 24

entity set

Back 24

used for entity diagram. a table with the rows being entities

Front 25

class diagram

Back 25

refers to Unified Modeling Language. used to represent data and their relationships in the DB

Front 26

class

Back 26

OO model. similar objects that share structure and methods

Front 27

class hierarchy

Back 27

OO model. an upside down tree. CUSTOMER and EMPLOYEE classes have the PERSON parent class

Front 28

OODBMS

Back 28

Object Oriented Database Management System.

Front 29

Semantic data model

Back 29

OO model. 'semantic' means greater meaning. A class does many things. methods etc

Front 30

ERDM

Back 30

extended relational data model. a relational object oriented model.

Front 31

external model

Back 31

end user's view of the data enviroment

Front 32

conceptual model

Back 32

global view of the entire database as view by the entire organization. avoids details. independent of hardware and software

Front 33

logical design

Back 33

refers to creating a conceptual model that can implemented by any DBMS

Front 34

internal model

Back 34

refers to how the conceptual model fits into a DBMS. It has tables and their relationships. Fields and field types too.

Front 35

Physical model

Back 35

Describes how the machinery works, data saved on disk, etc.