Modern Database Management - Chapter 2 Flashcards

Vocabulary flashcards based on the lecture notes for Chapter 2 of Modern Database Management, focusing on data modeling in the organization.

Entity Instance

A single occurrence of an entity type; person, place, object, event, concept (often corresponds to a row in a table).

Entity Type

A collection of entities that share common properties or characteristics (often corresponds to a table).

Relationship Instance

A link between entities (corresponds to primary key–foreign key equivalencies in related tables).

Relationship Type

Category of relationship; link between entity types.

Attributes

Properties or characteristics of an entity or relationship type (often corresponds to a field in a table).

Business Rules

Statements that define or constrain some aspect of the business, derived from policies, procedures, events, functions; assert business structure; control/influence business behavior; are expressed in terms familiar to end users; are automated through DBMS software.

Data Definition

Explanation of a term or fact. A concise description of essential data meaning, gathered in conjunction with systems requirements, accompanied by diagrams, achieved by consensus and iteratively refined.

Entity

A person, a place, an object, an event, or a concept in the user environment about which the organization wishes to maintain data.

Strong Entity

Exists independently of other types of entities and has its own unique identifier.

Weak Entity

Dependent on a strong entity (identifying owner); cannot exist on its own; does not have a unique identifier (only a partial identifier).

Identifying Relationship

Links strong entities to weak entities.

Attribute

Property or characteristic of an entity or relationship type.

Composite Attribute

An attribute that has meaningful component parts (sub-attributes).

Multivalued Attribute

May take on more than one value for a given entity (or relationship) instance.

Derived Attribute

Values can be calculated from related attribute values (not physically stored in the database).

Identifier (Key)

An attribute (or combination of attributes) that uniquely identifies individual instances of an entity type.

Candidate Identifier

An attribute that could be an identifier; it satisfies the requirements for being an identifier.

Unary Relationship

Entities of the same entity type related to each other.

Binary Relationship

Entities of one type related to entities of another type.

Ternary Relationship

Entities of three different types involved in the same relationship.

One-to-One Relationship

Each entity in the relationship will have exactly one related entity.

One-to-Many Relationship

An entity on one side of the relationship can have many related entities, but an entity on the other side will have a maximum of one related entity.

Many-to-Many Relationship

Entities on both sides of the relationship can have many related entities on the other side.

Cardinality Constraints

The number of instances of one entity that can or must be associated with each instance of another entity.

Associative Entity

Combination of relationship and entity.

Time Stamp

A time value that is associated with a data value, often indicating when some event occurred that affected the data value.