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Chapter 2 MySql

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Section 1

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Participants

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SQL

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Mar 1, 2020

Cards (28)

Section 1

(28 cards)

Participants

Front

An ER term for entities that participate in a relationship. For example, in the relationship "PROFESSOR teaches CLASS," the teaches relationship is based on the participants PROFESSOR and CLASS.

Back

single-valued attribute

Front

An attribute that can have only one value.

Back

Binary Relationship

Front

An ER term for an association (relationship) between two entities. For example, PROFESSOR teaches CLASS.

Back

Relationship degree

Front

The number of entities or participants associated with a relationship. A relationship degree can be unary, binary, ternary, or higher.

Back

Existence-Independent

Front

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.

Back

non-identifying relationship

Front

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

Back

Mandatory Participation

Front

A relationship in which one entity occurrence must have a corresponding occurrence in another entity. For example, an EMPLOYEE works in a DIVISION. (A person cannot be an employee without being assigned to a company's division.)

Back

Weak relationship

Front

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

Back

Optional Attribute

Front

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

Back

Simple attribute

Front

An attribute that cannot be subdivided into meaningful components. Compare to composite attribute.

Back

Identifiers

Front

One or more attributes that uniquely identify each entity instance.

Back

Unary relationship

Front

An ER term used to describe an association within an entity. For example, an EMPLOYEE might manage another EMPLOYEE.

Back

Cardinality

Front

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.

Back

Relational schema

Front

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

Back

Multivalued attributes

Front

An attribute that can have many values for a single entity occurrence. For example, an EMP_DEGREE attribute might store the string "BBA, MBA, PHD" to indicate three different degrees held.

Back

Composite Attribute

Front

An attribute that can be further subdivided to yield additional attributes. For example, a phone number such as 615-898-2368 may be divided into an area code (615), an exchange number (898), and a four-digit code (2368). Compare to simple attribute.

Back

Iterative Process

Front

A Process based on repetition of steps and procedures

Back

Derived attribute

Front

An attribute that does not physically exist within the entity and is derived via an algorithm. For example, the Age attribute might be derived by subtracting the birth date from the current date.

Back

Required attribute

Front

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

Back

strong (identifying) relationship

Front

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.

Back

Ternary relationship

Front

An ER term used to describe an association (relationship) between three entities. For example, a DOCTOR prescribes a DRUG for a PATIENT.

Back

Optional Participation

Front

In ER modeling, a condition in which one entity occurrence does not require a corresponding entity occurrence in a particular relationship.

Back

strong entity

Front

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

Back

Weak Entity

Front

An entity that displays existence dependence and inherits the primary key of its parent entity. For example, a DEPENDENT requires the existence of an EMPLOYEE.

Back

Existence-Dependent

Front

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.

Back

Regular Entity

Front

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

Back

Composite Identifier

Front

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

Back

Recursive Relationship

Front

A relationship found within a single entity type. For example, an EMPLOYEE is married to an EMPLOYEE or a PART is a component of another PART.

Back