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C&IT 180 Introduction to Systems Design Sample Exam #2 True/False Questions 50 questions @ 1 point each = 50 points 1. An entity is something about which the
business needs to store data.
2. An attribute is a descriptive property
or characteristic of an entity.
3. Example data types include: numbers,
text, memo, date, time, yes/no, Boolean, value set, or image.
4. A key is an attribute, or group of
attributes, that assumes a unique value for each entity instance. It is sometimes called an identifier.
5. An alternate key is that candidate key
that will most commonly be used to uniquely identify a single entity instance.
6. A relationship is a natural business
association that exists between one or more entities.
7. All data model relationships are
unidirectional.
8. A recursive relationship identifies a
relationship that may exist between different instances of the same entity.
9. A foreign key in a child entity always matches
the primary key in the parent entity.
10. An entity subtype is an entity whose
instances inherit some common attributes from an entity supertype and then add
other attributes that are unique to an instance of the subtype.
11. A good data model is essentially
redundant to ensure data integrity.
12. Data analysis is a process that prepares
a logical model for implementation as a redundant, explicit, and finite
database through a technique called generalization.
13. Process modeling is a technique for
organizing and documenting the structure and flow of data through a system's
processes and /or the logic, policies and procedures to be implemented by a
system's processes.
14. Logical models show not only what a
system is or does, but also how the system is implemented.
15. An entity relationship diagram (ERD) is a
tool that depicts the flow of data through a system and the work or processing
performed by that system.
16. A process is work performed on, or in
response to, incoming data flows or conditions.
A synonym is transform.
17. Decomposition is the act of breaking a
system into component subsystems, processes and subprocesses.
18. Primitive processes are the lowest level
of detail when depicted in a process model.
19. Structured English is a language and
syntax, based on the relative strengths of structured programming and natural
English, for specifying the underlying logic of elementary processes on process
models such as data flow diagrams.
20. A composite data flow is a data flow that
consists of other data flows. They are
used to combine similar data flows on high-level data flow diagrams to make
those diagrams easier to read.
21. The packet concept is critical to the creation
of data flow diagrams. Data that should
travel together should be shown as a single data flow, no matter how many
physical documents or attributes are included in the data flow.
22. Data stores are data in motion, and data
flows are data at rest.
23. Balancing is the synchronizing of data
flow diagrams at different levels of detail to preserve consistency and
completeness of the models.
24. An external agent defines a person,
organization unit, other system or other organization that lies outside the
scope of the project but that interacts with the system being studied.
25. An object is something that is or is
capable of being seen, touched, or otherwise sensed, and about which users
store data and associate behavior.
26. Behavior refers to those things that the
object can do and that correspond to functions that act on the object's data
(or attributes). This is commonly
referred to as a method, operation or service.
27. Object-oriented analysis (OOA) techniques
are used to (1) study existing objects to see if they can be reused or adapted
for new uses; and (2) define new or modified objects that will be combined with
existing objects into a useful business computing application.
28. Inheritance means that methods and
attributes defined in an object class can be inherited or reused by another
object class.
29. Encapsulation means "many
forms." Applied to object-oriented techniques, it means that the same
named behavior may be completed differently for different objects/classes.
30. Class diagrams depict the system's object
structure. They show object classes that
the system is composed of as well as the relationships between those classes.
31. Activity diagrams are used to graphically
depict the sequential flow of activities of either a business process or a use
case. They can also be used to model
actions that will be performed when an operation is executing as well as the
results of those actions.
32. Deployment diagrams describe the physical
architecture of the hardware and software in the system. They depict the software components,
processors and devices that make up the system's architecture.
33. A class diagram is used to graphically
depict the objects and their associations and relationships, including:
multiplicity, associations, generalization/specialization relationships, and
aggregation relationships.
34. Attributes are the data that represents
characteristics of interest about an object.
35. Use case diagrams graphically depict the
interactions between the system and external systems and users. In other words, they graphically describe who
will use the system and in what ways the user expects to interact with the
system.
36. An object instance is a specific person,
place, thing or event, as well as the values for the attributes of that object.
37. Multiplicity is the minimum and maximum
number of occurrences of one class for a single occurrence of the related
class.
38. Duplication of data items in multiple
files is normally cited as the principal disadvantage of file-based systems.
39. Conventional files are relatively
difficult to design and implement because they are normally designed for use
with multiple applications or information systems.
40. As enterprise systems and applications
are re-engineered, the trend is overwhelmingly in favor of replacing database
systems and applications with legacy file-based systems and applications.
41. Realistically, most organizations build
several databases, each one sharing data with several information systems.
Thus, there will be some redundancy between databases. However, this redundancy
is both greatly reduced and ultimately, controlled.
42. Database technology offers the advantage
of storing data in flexible formats. This is made possible because databases
are defined separately from the information systems and application programs
that will use them. Theoretically, this allows us to use the data in ways not
originally specified by end-users. This is known as data independence.
43. The database system advantages of data
independence, greatly reduced data redundancy, and increased flexibility come
at a cost. Database technology requires a significant investment based on the
learning curve required to use the database technology, and the necessity to
adhere to rigorous design principles.
44. A secondary key is an alternate
identifier for a database. Its value may identify either a single record or a
subset of all records.
45. Foreign keys are pointers to the records
of a different file in a database. Foreign keys are how the database links the
records of one type to those of another type.
46. An entity is in first normal form (1NF)
if there are no attributes that can have more than one value for a single
instance of the entity (frequently called repeating groups). Any attributes that
can have multiple values actually describe a separate entity.
47. Transaction files or tables contain
records that describe business events. The data describing these events
normally has a limited useful lifetime. Subsequent to their useful lifetime,
they are archived off-line.
48. The data manipulation language (DML) is
used by the DBMS to physically establish those record types, fields, and
structural relationships. Additionally, the DML defines views of the database.
49. Relational databases implement data in a
series of two-dimensional tables that are "related" to one another
via foreign keys. Each table (sometimes called a relation) consists of named
column (which are fields or attributes) and any number of unnamed rows (which
correspond to records).
50. An entity is in second normal form (2NF)
if it is already in 1NF and if the values of all non-primary key attributes are
dependent on the full primary key, not just part of it. Any non-key attributes
that are dependent on only part of the primary key should be moved to any
entity where that partial key becomes the full key.
Multiple Choice Questions 25 questions @ 2 points each = 50 points 51. An entity relationship diagram: A) is used in data modeling. B) depicts data in terms of entities and
relationships. C) identifies the cardinality of a relationship.
D) makes clear the degree of a relationship. E) all of the above. 52. An entity: A) is something about which the business needs
to store data. B) is a class of persons, places, objects,
events or concepts about which we need to capture and store data. C) is usually represented as a diagram. D) can have many attributes. E) all of the above. 53. A data type: A) defines what type of data can be stored in an
attribute. B) could be text, number, date, time, yes/no,
value set or image. C) consists of compound attributes. D) both (A) and (B). E) none of the above.
54. What defines the minimum and maximum
number of occurrences of one entity that may be related to a single occurrence
of the other entity? A) the domain B) the concatenation C) an associative entity D) the cardinality E) none of the above
55. An entity that inherits its primary key
from more than one entity is called: A) an associative entity B) a concatenated entity C) a degree of 3 D) a many-to-many cardinality E) none of the above
56. The process that prepares a data model
for implementation as a simple, nonredundant, flexible and adaptable database
is known as: A) process analysis B) requirements analysis C) data analysis D) generalization E) none of the above
57. A technique for organizing and
documenting the structure and flow of data through a system's processes and or
the logic, policies and procedures to be implemented by a system's processes is
known as: A) data modeling B) process modeling C) context modeling D) operational modeling E) none of the above
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