CIS Chapter 1-4

Operational Data

Data related to current operations, such as daily revenue.

Informational Data

Data that can include historical information and context.

DB

Abbreviation for Database, an organized collection of related data.

Data

Stored representations of meaningful objects and events, like names or birthdays.

Structured Data

Data that is organized in a defined format, such as numbers and text.

Unstructured Data

Data that does not have a predefined format, such as images and videos.

DBA

Database Administrator, responsible for managing databases.

DBMS

Database Management System, software for managing databases.

Data Management

The process of handling data for personal or organizational use.

Multi-tiered

A database architecture suitable for small companies.

Enterprise

A larger scale of data management, often involving complex systems.

Information

Data that has been processed to enhance knowledge.

Processed Data

Data that has been transformed into meaningful information.

Metadata

Data that describes the properties and context of user data.

Data Models

Abstract models that organize data descriptions and constraints.

Conceptual Data Model

Defines what the system contains, created by stakeholders.

Logical Data Model

Defines how the system should be implemented, regardless of DBMS.

Physical Data Model

Describes how the system will be implemented using a specific DBMS.

Entities

Descriptions of people, places, objects, events, or concepts.

Attributes

Characteristics or properties of an entity.

Primary Key

Unique attributes that identify an entity instance.

Foreign Key

An attribute that creates a link between two entities.

Relationships

Connections between entities, such as parent-child relationships.

One-to-Many Relationship

A relationship where one entity can relate to many instances of another.

Many-to-Many Relationship

A relationship requiring a bridge entity to connect multiple instances.

ERD

Entity-Relationship Diagram, a visual representation of entities and relationships.

Required Attribute

An attribute that must be present in each entity instance.

Optional Attribute

An attribute that may not have a value.

Composite Attribute

An attribute that consists of meaningful parts.

Simple Attribute

An attribute that cannot be broken down further.

Multivalued Attribute

An attribute that can have multiple values for a single entity instance.

Derived Attribute

An attribute whose value can be calculated from other attributes.

Identifier

An attribute that distinguishes individual instances of an entity.

Relationship Type

A meaningful association between entity types.

Cardinality Constraint

Rules specifying the number of instances in a relationship.

Time Stamp

A time value associated with a data value indicating when an event occurred.

Enhanced Entity Relationship (EER)

A model extending the original E-R model with new constructs.

Subtype

A subgroup of entities within a larger entity type.

Supertype

A generic entity type that has relationships with one or more subtypes.

Attribute Inheritance

Subtypes inherit attributes from their supertype.

Generalization

Defining a more general entity type from specialized types.

Specialization

The process of defining one or more subtypes of the supertype and forming supertype/subtype relationships

Completeness Constraint

A type of constraint that addresses whether an instance of a supertype must also be a member of at least one subtype

Total Specialization Rule

Each supertype instance must belong to at least one subtype.

Partial Specialization Rule

A supertype instance may not belong to any subtype.

Disjointness Constraint

Specifies if a supertype instance can belong to multiple subtypes.

Subtype Discriminator

An attribute determining the target subtype for an instance.

Data Structure

Organization of data in tables, rows, and columns.

Relation

A two-dimensional table of data.

Composite Key

A primary key consisting of more than one attribute.

Null

A value assigned when no other value applies.

Entity Integrity Rule

No primary key attribute may be null.

Referential Integrity Constraint

Foreign key values must match primary key values or be null.

Well-Structured Relation

A relation with minimal redundancy and no anomalies.

Anomaly

An inconsistency that arises from redundant data.

Regular Entity

An entity with independent existence, representing real-world objects.

Weak Entity

An entity dependent on a regular entity for its existence.

Associative Entity

An entity formed from a many-to-many relationship.

Surrogate Primary Key

A system-assigned primary key for a relation.

Normalization

The process of organizing data to minimize redundancy and anomalies.

Normal Form

A state of relation that requires that certain rules regarding relationships between attributes are satisfied

First Normal Form

Any multivalued attributes that have been removed so that there is a single value 

Second normal Form

Any partial functional dependencies have been removed, Entity whose non primary key attributes are dependent of the full primary key

Third Normal Form

Any transitive dependencies have been removed Entity whose primary key attributes are not dependent on any other non primary key attribute

Goals of normalization

Minimize data redundancy, this avoids anomalies and conserves storage space, Simplify the enforcement of referential integrity constraints, Make it easier to maintain data (insert, update, and delete), Provide a better design that is an improved representation of the real world and a stronger basis for future growth

Insertion

adding new rows forces user to create duplicate data

Deletion

deleting rows may cause a loss of data that would be needed for other future rows

Modification

changing data in a row forces changes to other rows because of duplication

Overlap Rule

A rule that specifies that an instance of a supertype may simultaneously be a member of two or more subtype