Business Driven Information Systems Appendix C
Terms in this set (26)
logical data structures that detail the relationships among data elements using graphics or pictures.
Relational Database Model
stores information in the form of logically related two-dimensional tables.
Entity Relationship Diagram
a technique for documenting the entities and relationships in a database environment.
stores information about a person, place, thing, transaction, or event.
cannot be broken down into a smaller component.
can be divided into smaller components
Single Valued Attribute
having only a single value of each attribute of an entity.
Multi Valued Attribute
having the potential to contain more than one value for an attribute.
the attribute that is used to derive the attribute. date of birth
an attribute that can be calculated using the value of another attribute. age
Null Valued Attribute
assigned to an attribute when no other value applies or when a value is unknown.
a statement that defines an aspect of a business.
one to one, one to many, many to many
Types of relationships among entities
one to one relationship
a relationship between two entities in which an instance of one entity can be related to one one instance of a related entity.
one to many relationship
a relationship between two entities in which an instance of one entity can be related to many instances of a related entity.
Many to many relationship
between two entities in which an instance of one entity is related to many instances of another and one instance of the other can be related to many instances of the first entity.
entities that exist to represent the relationship between two other entities.
expresses the specific number of instances in an entity.
composed of rows and columns that represent an entity.
a characteristic of a table.
a collection of related data elements.
a field (or group of fields) that uniquely identifies a given record in a table.
a primary key of one table that appears as an attribute in another table and acts to provide a logical relationship between the two tables.
maintains information about various types of objects, events, people, and places.
Database Management System
creates, reads, updates, and deletes data in a database while controlling access and security.
Entities and attributes
Relational database model components