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Glossary of ISOM Quiz II Chpt 7

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Created by ddeetz

stores information in the form of logically related two-dimensional tables
Relational Database Model
person, place, object, event, concept
Entity
property or characteristic of an entity

exmp: birthdate

Attribute
An attribute that uniquely identifies individual instances of an entity.
Key Attribute
an association among the instances of entity types
Relationship
the number of instances of one entity that can or must be associated with each instance of another entity

optional, mandatory, one, many

Cardinality Constraints
a two dimensional table
relation
a collection of related relations
within one database every relation has a unique name
relational database
Within a relation
Columns have unique names.
Every row is unique.
Every column value for every row is single-valued
All values in a column are values from the same domain.
The order of the columns is irrelevant.
The order of the rows is irrelevant




uniquely identifies a row in a relational table
equivalent to the Key attribute in the ER model
Primary Key
used to implement relationships (one-to-one, one-to-many, many-to-many) in relational model
depicted by the Referential Integrity Constraint:
a line with an arrow pointing from the foreign key to its source

Foreign Key
No primary key attribute may be null
Entity Integrity
if a Table A contains a foreign key that matches the primary key of the Table B then values of this foreign key either must match the value of the primary key for some row in table B, or must be null
Referential Integrity
Databases reduce information ________
Redundancy
________is one of the primary problems with redundant information
Inconsistency
Databases offer several security features including
Passwords
Access levels
Access controls

software through which users and application programs interact with a database
Database Management System (DBMS)
allows user to create tables and relationships
Data Definition Component
allows users to create, read, update, and delete information in a database
Data Manipulation Component
allows users to create various interfaces to databases
Application generation component
allows DBA (Data Base Administrator) to maintain technical aspects of database systems (such as performance, security, etc.)
Data Administration Component

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