Chapter 17 Flashcards
data modeling
defining a database so that it faithfully represents all key components of an organizations environment. The objective is to explicitly capture and store data about every business activity the organization wishes to plan, control, or evaluate
entity-relationship (E-R) diagram
a graphical depiction of a databases contents showing the various entities being modeled and the important relationships among them
entity
anything about which an organization wants to collect and store information
REA data model
a data model used to design AIS databases . It contains information about three fundamental types of entities; resources, events and agents
resources
those things that have economic value to an organization such as cash, inventory, supplies, factories, and land
events
business activities about which management wants to collect information for planning or control purposes
agents
the people and organizations who participate in events and about whom information is desired
cardinalities
describe the nature of a database relationship indicating the number of occurrences of one entity that may be associated with a single occurrence of the other entity. Three types of cardinalities are one to one, one to many, and many to many
minimum cardinality
the minimum number of instances that an entity can be lined to the other entity in the relationship. Only two options, 0 and 1
maximum cardinality
the max number of instances that an entity can be lined to the other entity in the relationship. Only two options; 1 or many
one to one relationship (1:1)
a relationship between two entities where the max cardinality for each entity is 1
one to many (1:N) relationship
a relationship between two entities where the max cardinality for one of the entities is 1 but the other entity has a max cardinality of many
many to many relationship (M:N)
a relationship between 2 entities where the max cardinality of both entities is many
