IS 441, Quiz1,2/Chp1-4 terms
A person's name, birthday, and social security number are all examples of:
Attributes
The total quiz points for a student for an entire semester is a(n) ______ attribute.
Derived
The logical representation of an organization's data is called a(n):
Entity-relationship Model
In prototyping, implementation and maintenance activities are repeated as necessary until the product is correct.
True
Information is processed data.
True
The overlap rule specifies that if an entity instance of the supertype is a member one subtype, it can simultaneously be a member of two (or more) subtypes.
True
Composite Identifier
an identifier that could be a key...satisfies the requirements for being an identifier
Primary Key
are unique identifiers of the relation. Ex. include employee numbers, SSN, etc..; This guarantees that all rows are unique
Entity Instance
single, occurrence of an entity type
Associative Entity
the combination of relationship and entity.
Derived Attribute
values can be calculated from related attribute values (not physically stored in the database)
Completeness Constraint
whether an instance of a supertype must also be a member of at least one subtype. Total Specialization Rule: Yes (double line) Partial Specialization Rule: No (single line)
Strong Entity
exists independently of other types of entities; own unique identifier; identifier underlined with single line
Minimum Constraint
if zero, then optional; one or more, then mandatory
Composite Key
is a combination of two or more columns in a table that can be used to uniquely identify each row in the table
Enhanced entity-relationship (EER) model
is a high-level or conceptual data model incorporating extensions to the original entity-relationship (ER) model, used in the design of databases.
Ternary Relationship
is when three entities participate in the relationship.
Multivalued Attribute
may take on more than one value for a given entity (or relationship) instance
The SDLC phase in which the detailed conceptual data model is created is the ______ phase.
Analysis
A graphical system used to capture the nature and relationships among data is called a(n):
Data Model
Disjointness Constraint
whether an instance of a supertype may simultaneously be a member of two (or more) subtypes
Disjoint Rule
An instance of the Supertype can be only ONE of the subtypes
Identifier (Key)
an attribute (or combination of attributes) that uniquely identifies individual instances of an entity type
Subtype Discriminator
an attribute of the supertype whose values determine that target subtype(s)
The SDLC phase in which every data attribute is defined, every category of data is listed and every business relationship between data entities is defined is called the ______ phase.
Analysis
Relationship Instance
is between specific entity instances
Business Rules
must be described along with the data to which they are related. Statements that define or constrain some aspect of the business; derived from policies, procedures, events, functions; assert business structure; control/influence business behavior; expressed in familiar terms to end users; are automated through DBMS software.
Required Attribute
must have a value for every entity (or relationship) instance with which its associated
Maximum Cardinality
the maximum number
Generalization
the process of defining a more general entity type from a set of more specialized types; (BOTTOM-UP- from Specific to General)
Specialization
the process of defining one or more subtypes of the super types and forming supertype/subtype relationship; (TOP-DOWN- from General to Specific)
Entity-Relationship Model (E-R Model)
the structure for a database is portrayed as a diagram, called an entity-relationship diagram (or ER diagram), that resembles the graphical breakdown of a sentence into its grammatical parts. Entities are rendered as points, polygons, circles, or ovals.
The property by which subtype entities posses the values of all attributes of a supertype is called:
Attribute Inheritance
A cardinality constraint tells what kinds of properties are associated with an entity.
False
A member of a subtype does NOT necessarily have to be a member of the supertype.
False
A simple attribute can be broken down into smaller pieces.
False
A subtype is a generic entity that has a relationship with one or more entities at a lower level.
False
A ternary relationship is equivalent to three binary relationships.
False
Subtypes at the lowest level of a hierarchy do not inherit attributes from their ancestors.
False
The disjoint rule specifies that if an entity instance of the supertype is a member of one subtype, it MUST simultaneously be a member of another subtype.
False
Which of the following is NOT an advantage of database systems?
Redundant Data
A relationship where the minimum and maximum cardinality are both one is a(n) ______ relationship.
Mandatory One
A relationship where the minimum and maximum cardinality are both one is a(n) _______ relationship.
Mandatory One
Data that describes the properties of other data are: Logical, relationships, Physical or None
None of these.
In a supertype/subtype hierarchy, each subtype has:
Only one supertype
The subtype discriminator is a composite attribute when there is a(n):
Overlap Rule
Subtypes should be used when:
There are attributes that apply to some but not all instances of an entity type
In an E-R diagram, there are ______ business rule(s) for every relationship.
Two
A subtype can become a supertype if the subtype has other subtypes beneath it.
True
In an E-R diagram, an associate entity is represented by a rounded rectangle.
True
The ______ rule specifics that an entity can be a member of only one subtype at a time.
Disjoint
A database is an organized collection of ______ related data.
Logically
Relation
is a named, two dimensional table of data; consists of rows (records) and columns (attributes or field)
Entity Type
collection of entities that share common properties or characteristics
Total Specialization
demands that every entity in the superclass belong to some subclass; a patient has to be either an Outpatient or a Resident Patient
Weak Entity
dependent on a strong entity, cannot exist on its own; does not have a unique identifier (partial identifier); entity box & partial identifier have double lines
Requirements for a table to qualify as a Relation:
must have a Unique Name; every attribute value must be Atomic (not multivalued, not composite); every ROW must be Unique (can't have two rows w/ exactly the same values for all their fields); attributes (columns) in TABLES must have Unique Names; the order of Columns/Rows must be Irrelevant
Unary Relationship
when both participants in the relationship are the same entity
Disjoint constraints
whether an instance of a supertype may simultaneously be a member of two (or more) subtypes
Identifying Relationship
links strong entities to weak entities
Entity
person, place, object, an event or a concept in the user environment about which the organization wished to maintain data
Entity Cluster
set of one or more entity types and associated relationships grouped into a single abstract entity type
Entity-Relationship Diagram (E-R Diagram)
shows the relationships of entity sets stored in a database; an entity in this context is a component of data. In other words, ER diagrams illustrate the logical structure of databases. At first glance an entity relationship diagram looks very much like a flowchart.
Referential Integrity Constraint
is a property of data stating references within it are valid. In the context of relational databases, it requires every value of one attribute (column) of a relation (table) to exist as a value of another attribute (column) in a different (or the same) relation (table)
Optional Attribute
may not have a value for every entity (or relationship) instance with which it is associated
An attribute that can be broken down into smaller parts is called a(n) ______ attribute.
Composite
The common types of entities are: Weak entities, Associative Entities, Strong entities, or All.
All of these
Which of the following conditions should exist if an associate entity is to be created? The new associate entity participates in independent relationships; All the relationships for the participating entities are many-to-many; The new associative entity has independent meaning; All of these.
All of these
Which of the following types of data can be stored in a database? Letters, Numbers, Voice, All of these
All of these
A ______ specifies the number of instances of one entity that can be associated with each instance of another entity.
Cardinality Constraint
A ______ constraint is a type of constraint that address whether an instance of a supertype must also be an instance of at least one subtype.
Completeness
An attribute that uniquely identifies an entity and consists of a composite attribute is called a(n):
Composite Identifier
Characteristics of a Good Business Rule
Declarative- what, not how; Precise-clear, agreed-upon meaning; atomic- one statement; consistent- internally and externally; expressible- structured, natural language; distinct- non-redundant; business-oriented-understood by business people.
The number of entity types that participate in a relationship is called the:
Degree
An ______ addresses whether an sentence of a supertype may simultaneously be member of two or more subtypes.
Disjointedness Constraint
Simple Attribute
E-R attributes map directly onto the relation
A person, place, an object, an event or concept about which the organization wishes to maintain data is called a(n):
Entity
Which of the following is NOT a cost and/or risk of the database approach? Organized conflict, Improved responsiveness, Cost of conversion, or Specialized personnel
Improved Responsiveness
One disadvantage of file processing systems is:
Limited Data Sharing
A student can attend five classes, each with a different professor Each professor has 30 students. The relationship of students to professor is a ______ relationship.
Many-to-many
Attribute
Properties or characteristics of an entity or relationship type
All of the following are primary purposes of a database management system (DBMS) EXCEPT: creating data, updating data, providing an integrated development environment, or storing data,
Providing an integrated development environment
Characteristics of an Associative Entity
Relationship should be many, has independent meaning, unique identifier, have other attributes, and ternary relationships should always be converted to associative
A centralized knowledge base of all data defines definitions, data relationships, screen and report formats, and other system components is called a(n):
Repository
An attribute that must have a value for every entity (or relationship) instance is a(n):
Required Attribute
The process of defining one or more subtypes of a supertype and forming relationships is called:
Specialization
Attribute Inheritance
Subtype entities inherit values of all attributes of the supertype; an instance of a subtype is also of the supertype
Which of the following is a generic entity type that has a relationship with one or more subtypes?
Supertype
In a supertype/subtype hierarchy, subtypes that are lower in the hierarchy inherit attributes from not only their immediate supertype but from all _______ in the hierarchy.
Supertypes
A simultaneous relationship among the instances of three entity types is called a(n) ______ relationship.
Ternary
Cardinality Restraints
The number of of instances of one entity that can or must be associated with each instance of another entity
Which of the following is a completeness constraint?
Total Specialization
Supertype
a generic entity type that has a relationship with one or more subtypes
Anomaly
Without normalization many problems can occur when trying to load an integrated conceptual model into the DBMS. These problems arise from relations that are generated directly from user views.
Degree
a relationship is the number of entity types that participate in it.
Subtype
a subgrouping of the entities in an entity that has attributes distinct from those in other subgrouping
Time Stamp
a time value that is associated with a data value often indicating when some event occurred that affected the data value
Composite Attribute
an attribute that has meaningful component parts. Ex. Employee Address (Street address, city, state, postal code) Employee address is the composite attribute & everything in the ( ) are the component attributes
Foreign Key
are identifiers that enable a dependent relation (on the many side of a relationship) to refer to its parent relation (on the side of the relationship)
Relationship Type
category of relationship...link between entity types; is modeled as lines between entity types
Strong Entity Type
exists independently of other types of entities; own unique identifier; identifier underlined with a single line
Partial Specialization
only some individuals of the parent class are specialized (that is, have unique attributes). Other individuals of the parent class have only the common attributes; A vehicle can be a car, or a truck, but does not have to be either
Binary Relationship
two entities are involved in a relationship
