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Entities

___________ in the ERM, it corresponds to a table—not to a row

Required Attributes

In ER modeling, an attribute that must have a value. In other words, it cannot be left empty.

Optional Attributes

In ER modeling, an attribute that does not require a value; therefore, it can be left empty.

Domains

The possible set of values for a given attribute.

Identifiers

One or more attributes that uniquely identify each entity instance.

Relational Schema

The organization of a relational database as described by the database administrator.

Composite Identifiers

In ER modeling, a key composed of more than one attribute

Composite Attribute

An attribute that can be further subdivided to yield additional attributes.

Simple Attribute

An attribute that can not be subdivided into meaningful components

Single-Valued Attributes

An attribute that can have only one value

Multivalued Attributes

An attribute that can have many values for a single entity occurrence.

Derived Attributes

An attribute that does not physically exist within the entity and is derived via an algorithm

Relationship

is an association between entities.

Participants

The entities that participate in a relationship are also known as ___________

Connectivity

the term _____ is used to describe the relationship classification.

Cardinality

A property that assigns a specific value to connectivity and expresses the range of allowed entity occurrences associated with a single occurrence of the related entity

Existence-dependent

A property of an entity whose existence depends on one or more other entities. In such an environment, the existence-independent table must be created and loaded first because the existence dependent key cannot reference a table that does not yet exist.

Existence-independent

A property of an entity that can exist apart from one or more related entities. Such a table must be created first when referencing an existence-dependent table.

Strong Entity (Regular Entity)

An entity that is existence-independent, that is, it can exist apart from all of its related entities.

Weak (Non-Identifying) Relationships

A relationship in which the primary key of the related entity does not contain a primary key component of the parent entity.

Strong (Identifying) Relationships

A relationship that occurs when two entities are existence dependent; from a database design perspective, this relationship exists whenever the primary key of the related entity contains the primary key of the parent entity

•The entity is existence-dependent; it cannot exist without the entity with which it has a relationship.

•The entity has a primary key that is partially or totally derived from the parent entity in the relationship.

In contrast to the strong or regular entity, a weak entity is one that meets two conditions:

optional / mandatory

Participation in an entity relationship is either _________ or ________

False

True/False Relationships aren't bidirectional

Relationship Degree

indicates the number of entities or participants associated with a relationship

Unary Relationship

An ER term used to describe an association within an entity

Binary Relationship

An ER term for an association (relationship) between two entities.

Ternary Relationship

An ER term used to describe an association (relationship) between three entities.

Recursive Relationship

A relationship found within a single entity type.

Associative Composite Entities

M:N relationships are a valid construct at the conceptual level, and therefore are found frequently during the ER modeling process.

Associative Entity

The ER Model (Associative Composite Entities) uses _________ to represent an M:N relationship between two or more entities.

Associative Composite Entities

also called a composite or bridge entity

conflicting goals

Database designers must often make design compromises that are triggered by _____________, such as adherence to design standards (design elegance), processing speed, and information requirements.

Design Standards

Such standards guide you in developing logical structures that minimize data redundancies, thereby minimizing the likelihood that destructive data anomalies will occur.

processing speed

High _______________ means minimal access time, which may be achieved by minimizing the number and complexity of logically desirable relationships

information requirements

Complex ________________ may dictate data transformations, and they may expand the number of entities and attributes within the design

Conflicting Goals

Occasionally, design and implementation problems do not yield "clean" implementation solutions

SQL Functions

MySQL functions are defined as named, reusable sequence sof SQL statements. They can take zero or more arguments as input and performspecific operations based on these arguments

Relational Set Operations

refer to a set of functions that allow you to combineresults from multiple SELECT statements by performing mathematical setoperations like "union," "intersection," and "set difference"