database midterm 1

Grid computing model efficiency

A computing architecture where system resources are pooled together for maximum efficiency.

Software components required for user access to business applications

Operating System software, Internet Browser software, and Graphical User Interface (GUI) software.

Hardware and software dependency

Software cannot operate without underlying hardware.

E.F. Codd's contribution to computer science

Pioneered research in the early 1970s that led directly to the creation of Relational Databases.

Data vs Information distinction

Data consists of raw stored facts, whereas Information is processed data obtained by querying or accessing data to provide utility and context.

Conceptual Model vs Physical Model

Conceptual models (such as ERDs) capture business requirements independently of hardware or software implementation, while Physical models specify actual database implementation details.

Primary purpose of data modeling

To facilitate business discussions, control system scope, and create a blueprint for designing physical database systems.

Entity in data modeling

Something of significance to the business about which data must be collected and stored (typically named with a singular noun).

Volatile attribute

An attribute whose value changes over time (e.g., Age), as opposed to non-volatile attributes (e.g., Date of Birth).

ERD Unique Identifier (#) notation

A # symbol placed in front of an attribute indicates that it forms part of the Unique Identifier (UID).

Three required properties of every relationship in an ERD

Name, optionality, and cardinality.

ERD symbols for Cardinality

Crow's foot to represent 'many' and single toe to represent 'one'.

ERDish

The standardized language spoken when reading ERD relationships in both directions (left-to-right and right-to-left).

Matrix Diagrams in data modeling

Diagrams created before an ERD to ensure all entity relationships are identified; they do not display optionality or cardinality.

Structural business rules

Rules that specify what data to store and how data elements relate to each other (e.g., 'All employees must belong to a department').

Handling complex business rules outside ERD capabilities

Documenting constraints on a separate list to be enforced programmatically via software code.

Supertype and Subtype entity relationship rules

A subtype is drawn inside a supertype's softbox, every subtype instance must be an instance of the supertype, and subtypes can have unique relationships not shared by the supertype.

Non-transferable relationship

A relationship between entity instances that cannot be moved or transferred once created; denoted on an ERD with a diamond symbol.

Resolving Many-to-Many (M:M) relationships

Creating an intersection entity between the two original entities, converting the M:M relationship into two One-to-Many (1:M) relationships.

Barred relationship in intersection entities

A relationship bar used when an intersection entity lacks its own attributes, allowing it to inherit Unique Identifiers from the parent entities.

Redundant relationship in data modeling

An unnecessary relationship that duplicates information already represented elsewhere in the ER model.

Transformation stage of Entities during database implementation

Entities in conceptual design are transformed into Tables during physical database design.

Core Oracle Academy curriculum subject areas

Data Modeling, SQL, and PL/SQL.