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CIS 223 Database Midterm Review- ECPI University,
Newport News
Unit 1
Question 1 provide(s) a description of the data characteristics and the set of relationships that link the data found within the database.
Metadata
Question 2 A data warehouse can store data derived from many sources.
True
Question 3 What are some reasons for studying file systems?
-Complexity of database design is easier to understand.
-Understanding file system problems helps to avoid problems with DBMS systems.
-Knowledge of file systems is useful for converting file systems to database
systems.
Question 4 Which of the following is an example of structured data?
A spreadsheet
Question 5 We are now said to be entering the "knowledge age."
True
Question 6 Data is a discipline that focuses on proper generation, storage and retrieval of data.
management
Question 7 The same data might be simultaneously structured and unstructured depending on the intended processing.
True
Question 8 A(n) develops when all required changes in the redundant data are not made successfully.
data anomaly
A query language is a procedural language.
False
Question 10 A(n) database is used by an organization and supports many users across many departments.
enterprise
Question 11 Initially the files within a computer file system were similar to manual files.
True
Question 12 exists when it is possible to make changes in the data storage characteristics without affecting the application program's ability to access the data.
Data Independence
Question 13 A(n) might be written by a programmer or it might be created through a DBMS utility program.
application program
Question 14 Information implies familiarity, awareness, and understanding knowledge as it applies to an environment.
False
Question 15 To reveal meaning, information requires.
context
Question 16 M:N relationships are not appropriate in a relational model.
True
Question 17 Each row in the relational table is known as an entity instance or entity occurrence in the ER model.
True
Question 18 End-user interfaces require the end user to manually generate SQL code.
False
Describe a conceptual model and its advantages. What is the most widely used conceptual model?
-The conceptual model represents a global view of the entire database by the entire
organization. It integrates all external views (entities, relationships, constraints, and
processes) into a single global view of the data in the enterprise. It's also the basis
for the identification and high- level description of the main data objects (avoiding
any database model- specific details).
-Some advantages would be: it provides a bird's-eye (macro) level view of the data
environment that is relatively easy to understand. It's also independent of both
software and hardware.
-The most widely used conceptual model used is the ER model.
Question 30 The data model is said to be a semantic data model.
object-oriented
Unit 2 Question 1 A null is created when you press the Enter key or the Tab key to move to the next entry without making a prior entry of any kind.
True
Question 2 All primary key entries are unique, and no part of a primary key may be.
null
Question 3 Fortunately, the problems inherent in the ---------------- relationship can easily be avoided by creating a composite entity.
many-to-many
Question 4 As rare as 1:1 relationships should be, certain conditions absolutely require their use.
True
Question 5 DBMSs use indexes for many different purposes.
True
Numeric data are data on which you can perform meaningful arithmetic procedures.
True
Question 7 What is the system catalog?
The system catalog is a detailed system data dictionary that describes all objects
within the database, including data about table names, the table’s creator and
creation date, the number of columns in each table, the data type corresponding to
each column, index filenames, index creators, authorized users, and access
privileges.
Question 8 A(n) is an orderly arrangement used to logically access rows in a table.
index
Question 9 The index key can have multiple attributes, this is called a(n) index.
composite
Question 10 The relationship should be rare in any relational database design.
Question 11 The DBMS can easily handle multivalued attributes.
False
Question 12 relationships are most common.
Binary
Question 13 The following step occurs first in the process of building an ERD:.
Create a detailed narrative of the organization's description of operations.
Question 14 All simple attributes are also single-valued.
False
Question 15 attributes can have many values.
Multivalued
Composite keys are useful as identifiers of weak entities, where the weak entity has a strong relationship with the parent entity.
identifying
Question 6 Generalization is based on grouping unique characteristics and relationships of the subtypes.
False
Question 7 One important inheritance characteristic is that all entity subtypes inherit their primary key attribute from their supertype.
True
Question 8 A(n) is the attribute in the supertype entity that determines to which entity subtype each supertype occurrence is related.
subtype discriminator
Question 9 completeness means that not every supertype occurrence is a member of a subtype.
Partial
Question 10 To model time-variant data, you must create a new entity in a M:N relationship with the original entity.
False
Question 11 One important inheritance characteristic is that all entity subtypes inherit their key attribute from their supertype.
primary
Question 12 The default comparison condition for the subtype discriminator attribute is the comparison.
equality
Question 13 Subtypes that contain nonunique subsets of the supertype entity set are known as subtypes.
overlapping
Question 14 Entity subtypes do not inherit the relationships in which the supertype entity participates.
False
When selecting a foreign key placement for a 1:1 relationship, place the PK of the entity on the mandatory side in the entity on the optional side as a FK, and make the FK mandatory when .
one side is mandatory and the other side is optional
Question 16 Specialization is based on grouping characteristics and relationships of the subtypes.
unique
Question 17 Composite primary keys are particularly useful as identifiers of composite entities, where each primary key combination is allowed only once in the relationship.
M:N
Question 18 The " " characteristic of a primary key states the following: The selected primary key must not be composed of any attribute(s) that might be considered a security risk or violation. For example, using a Social Security number as a PK in an EMPLOYEE table is not a good idea.
security-compliant
Question 19 If you use a surrogate key, you must ensure that the candidate key of the entity in question performs properly through the use of the " " and "not null" constraints.
unique index
Question 20 The constraint specifies whether each entity supertype occurrence must also be a member of at least one subtype.
completeness
Question 21 A design trap occurs when a relationship is improperly or incompletely identified and is therefore represented in a way that is not consistent with the real world.
True
Question 22 The property of enables an entity subtype to inherit the attributes and relationships of the supertype.
inheritance
Optional Questions from Second Attempt: Question 1 In what two cases are composite primary keys particularly useful?
As identifiers of composite entities
-In which each each primary key combination is allowed once in M:N relationship
As identifiers of weak entities
-In which weak entity has a strong identifying relationship with the parent entity
Question 2 A occurs when you have one entity in two 1:M relationships to other entities, thus producing an association among the other entities that is not expressed in the model.
fan trap
Question 3 Non-overlapping subtypes are subtypes that contain a(n) subset of the supertype entity set.
unique
Question 4 What do specialization hierarchies do?
Depicts the arrangement of higher-level entity supertypes (parent entities) and
lower-level entity subtypes (child entities).
Question 5 An entity cluster is considered "virtual" or " " in the sense that it is not actually an entity in the final ERD.
abstract
Question 6 An entity supertype can have disjoint or overlapping entity subtypes.
True
Question 7 Partial completeness is symbolized by.
a circle over a single line
Question 8 An entity cluster is a "virtual" entity type used to represent multiple entities and relationships in the ERD.
True
The entity supertype contains the common characteristics and the entity subtypes contain the unique characteristics of each entity subtype.
True
Question 10 keys work with primary keys to properly implement relationships in the relational model.
Foreign
Question 11 is the bottom-up process of identifying a higher-level, more generic entity supertype from lower- level entity subtypes.
Generalization
Question 12 If one exists, a data modeler uses a as the primary key of the entity being modeled.
natural identifier
Question 13 Composite primary keys are particularly useful as identifiers of composite entities, where each primary key combination is allowed in the M:N relationship.
only once
Question 14 A key is a real-world, generally accepted identifier used to uniquely identify real-world objects.
natural
Mid-Term Review
- Knowledge is the body of information and facts about a specific subject.
- Context is used to reveal the meaning of data.
- Metadata provide(s) a description of the data characteristics and the set of relationships that link the data found within the database.
- A desktop database is a single-user database.
- A(n) operational database is designed to support a company's day-to-day operations.
- Accurate, relevant, and timely information is the key to good decision making.
- The phrase database system refers to an organization of components that define and regulate the collection, storage, management and use of data within a database environment
- Data inconsistency exists when different and conflicting versions of the same data appear in different places.
- The term islands of information refers to scattered locations storing the same basic data.
