Study Guide for INFS 3770
CHAPTER 1
Data vs Information

CHAPTER 2 * Entity: Unique and distinct object used to collect and store data * Attribute: Characteristic of an entity * Relationship: Describes an association among entities * One-to-many (1:M) * Many-to-many (M:N or M:M) * One-to-one (1:1) * Constraint: Set of rules to ensure data integrity
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* Entity relationship diagram (ERD) * Uses graphic representations to model database components
=====================================================================================CHAPTER 3 * Database * Tables (entity, file, record type, relation) * Records (rows, instance, tuple) * Fields (attribute, column)
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Types of Keys * Composite key * A key composed of more than one attribute * Key attribute * Any attribute that is part of a key * Superkey * Any key that uniquely identifies each row

* Candidate key * A superkey without unnecessary attributes * Foreign key (FK) * An attribute whose values match primary key values in the related table * Referential integrity * FK contains a value that refers to an existing valid tuple (row) in another relation * Secondary key * Key used strictly for data retrieval purposes
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* Entity integrity * Each row (entity instance) in the table has its own unique identity * Nulls * No data entry * Not permitted in primary key * Should be avoided in other attributes