test review Flashcards
true or false: good decisions require good information derived from raw date
true
where is data best stored?
in a database
t or f: understanding file system characteristics is not important?
false
when is the database used?
almost everywhere like management, research, and administration.
true or false: it is important to understand how database work and interact with other apps?
true
what is information?
is the result of processing raw data to reveal meaning.
t or f: Raw data must be formatted for storage, processing, and presentation?
true
t or f: data are the foundation of information, which is the bedrock of knowledge?
true
what is data in relation to information?
data is the building block of information
information is produced by processing data.
information used to reveal the meaning of data.
why are accuracy, relevancy, and time information important?
for good decision-making.
what is data management focused on?
proper generation, storage, and retrieving of data.
what is a database?
shared, integrated computer structure that stores a collection of end-user data. metadata.
what is end-user data?
raw facts of interest to end user.
what is metadata?
data about data
it provides a description of data characteristics and relationships in data.
complements and expands value of data.
what is a database management system (DBMS)?
collection of programs
manages the structure and controls access to data.
t or f: DBMS is the intermediary between the user and the database?
true
t or f: database structure stored as file collection?
true
t or f: you can access files through the DBMS and many more?
false (only DBMS)
t or f: DBMS enables data to be shared?
true
t or f: DBMS does not integrate many users’ views of the data?
false
what are the advantages of DBMS?
improve data sharing.
improve data security.
better data integration.
minimize data inconsistency.
improve data access.
improve decision-making.
increase end-user productivity.
the database can be classified according to the:
number of users
database location
expected type and extent of use
t or f: single-user database supports one or more users at a time?
false (only one)
what is a desktop database?
single user runs on PC.
what is the difference between a centralized database and distributed database?
centralized database located at a single site.
a distributed database is data distributes across several different sites.
what is a data warehouse?
stores data used for tactical or strategic decisions.
types of data?
structured data: resulted from the formatting.
unstructured data: data exist in their original state
semistructured data: data have been processed to some extent.
what is an extensible markup language (XML)?
represents data elements in textual format.
what database does XML support?
semistructural XML data
why is a database design important?
it focuses on the design of database structure used for end-user data.
what is the difference between a well-designed and a poorly-designed database?
well-designed: facilitates data management
poorly-designed: causes difficult to trace errors
reasons for studying file systems?
complexity of database design is easier to understand
understanding it helps avoid problems with DBMS systems.
t or f: the content of each file folder is not logically related?
false
what is the difference between manual file systems and computerized file systems?
manual file systems served as a repository for small data collection.
computerized file systems are a data processing specialist in converting computer file structure from manual systems.
t or f: as the number of files decreases, file systems evolve?
False (increases)
initially, what does a computer file system resemble?
manual systems
t or f: each file used its own application program to store, retrieve, and modify data?
true
what is the difference between data, field, record, and file?
data are raw facts that do not have a meaning or little meaning.
field is a character or group of characters that have a specific meaning.
record is a logically connected set of one or more fields that describe a person, place, or thing.
a file is a collection of related records.
t or f: the ubiquitous use of personal productivity tools can introduce the same problems as the old file systems?
true
what is Microsoft excel?
widely used by business users and a database substitute
t or f: file systems were not an improvement over the manual systems?
false
how long were file systems were used?
more than two decates
t or f: many problems are unique to file systems?
false
t or f: even simple file system retrieval required extensive programming?
true
summary of file system limitation contain?
requires extensive programming.
can not perform ad hoc queries.
system administration is complex and difficult.
difficult to make changes to existing structures.
security features are likely to be inadequate.
what is structural dependence?
access to a file is dependent on its own structure.
t or f: all file system programs must be modified to conform to a new file structure?
true
what is structural independence?
change file structure without effecting data access
what is data dependence?
data access changes when data storage characteristics change.
what is data independence?
data storage characteristics do not effect data access.
t or f: practical significance of data dependence is different between logical and physical data?
true
what is the difference between logical and physical format?
the logical format is how human views the data.
the physical format is how computers must work with data.
each program must contain?
lines specifying the opening of specific file types.
record specifications.
field definition.
t or f: file system structure does not make it difficult to combine data from multiple resources?
false
t or f: organizational structure promotes storage of the same data in different locations?
true
t or f: data stored in different locations are unlikely to be updated consistently?
true
what is data redundancy?
same data stored unnecessarily in different locations.
what is data inconsistency?
different and conflicting versions of the same data occurs in different places.
what is data anomalies?
abnormalities when all changes in redundant data are not made correctly.
to avoid data anomalies you have to?
update anomalies
insertion anomalies
deletion anomalies
t or f: most users lack the skill to properly design databases despite having multiple productivity tools available.
true
t or f: data modeling skills are not vital in the data design process?
false
t or f: good data modeling facilitates communication between designer, user, and developer?
true
t or f: database system consists of logically related data stored in multiple logical data repository?
false, only one data repository
t or f: DBMS eliminates most of the file system’s problems?
true
what is the database system environment?
defines and regulates the collection, storage, management, and use of data.
what are the five major parts of the database systems?
hardware
software
people
procedures
data
what is the difference between software and hardware?
hardware is the physical device.
software is the programmed devices and there are three types of software required:
operating system software.
DBMS software.
application programs and utility software.
who are the people in the database system?
all users of the database:
system and database admins
designers
system analysts and programmers
end-users
what are the procedures?
instructions and rules that govern the design and use of the database system
what is the data?
the collection of facts stored in the database.
t or f: database systems are created and managed at the same level of complexity?
false (at different levels)
t or f: database solutions must be cost-effective as well as tactically and strategically effective?
true
why are most functions are transparent to end users?
cause it can only be achieved through the DBMS
what does a data dictionary do?
DBMS stores definitions of data elements and relationships (metadata) in a data dictionary.
looks up required data component structures and relationships.
changes automatically recorded in the dictionary.
DBMS provides data abstraction and removes structural and data dependency
what does data storage management do?
DBMS creates and manages complex structures required for data storage
also stores related data entry forms, screen definition, record definition, etc
performance tuning
DBMS stores data in multiple physical files
what is performance tuning?
activities that makes the database perform more efficiently.
what do data transformation and presentation do?
DBMS transforms data entered to conform to a required data structure.
DBMS transforms physically retrieved data to conform to the user’s expectations.
what does data security do?
DBMS creates a security system that enforces user privacy and security.
security rules determine which users can access the database, which items can be accessed, etc.
what does multiuser access control do?
DBMS uses sophisticated algorithms to ensure concurrent access does not effect integrity
what do backup and recovery management do?
DBMS provides data backup and data recovery to ensure data safety and integrity.
it deals with recovery after a failure
what do backup and recovery management do?
DBMS provides data backup and data recovery to ensure data safety and integrity.
it deals with recovery after a failure
it is critical to preserving database integrity
what does data integrity do?
promotes and enforces integrity rules
minimize redundancy
maximize consistency
data relationships stored in a data dictionary used to enforce integrity
integrity is especially important in a transaction-oriented database system
what do database access languages and application programming interfaces do?
provides access through a query language
query language is a nonprocedural language
structure query language (SQL) is de facto query language
what do database communication interfaces do?
current DBMS accept end-user request via multiple different network environments.
what are the ways that communication is being accomplished?
end users generally answer query Qs by filling in screen forms through web browsers.
DBMS automatically publishes predefined reports on a web site.
DBMS connects to third party systems to distribute information via E-mail.
what does a database system provides a framework in which strict procedures and standers enforced do?
role of human changes from programming to managing organizational resources.
t or f: database system enables more sophisticated use of data?
true
t or f: data structures create within the database and their relationship determine effectiveness?
true
what are the disadvantages of a database system?
increase cost
management complexity
maintain currency
vendor dependence
frequent update/replacement cycles
chapter 2
the process that establishes need for and extent of information system. this is the def of?
system analysis
the process of creating information system?
systems developement
transforms data into information that forms basis for decision making?
applications
usually, applications produce the following?
formal report
tabulation
graphic displays
the applications are composed into two parts. what is it?
data
code
performance depends on three factors, what is it?
DB design and implementation
application design and implementation
administrative procedures
the process of DB design and implementation. this is the def of?
DB developement
The implementation phase includes:
creating DB storage structure
loading data into the database
providing for data management
what is SDLC stand for?
system development life cycle
how phases are in the SDLC?
5
planning
analyzing
designing
implementation
maintenance
the general overview of company and objectives. this is the def of?
planning
assessment of flow and extent requirements consists of three Q’s and they are?
should the existing system be continued
should the existing system be modified
should the existing system be replaced
studying and evaluating alternate solutions consists of?
tech aspects of hardware and software requirements
system cost
operation cost
the problems defined during planning phases are examined in greater detail during the?
analysis
t or f: analysis studies existing hardware and software
true
some of the goals in the analysis stages are a better understanding of:
system function area
actual and potential problems
oppertunities
the designer completes the design of system processes in which stage?
detailed system design
t or f: detailed system design includes all necessary technical specifications?
true
t or f: detailed system design are steps laid out for conversion from the old to the new system, and the training principles and methodologies are also planned
true
why are the detailed system design submitted?
for management’s approval
At which stage do the hardware, software, and application programs are installed?
implementation
until when the cycle of coding, testing, and debugging continues?
until database is ready for delivery
the database is created and the system is customized in which stage?
(creation of tables and views)
(user authorization)
implementation
three types of maintenance activity:
corrective
adaptive
perfective
what is CASE?
computer aided system engineering
t or f: CASE produces worse systems within a reasonable amount of time and at a reasonable cost?
false
t or f: CASE produced applications are structured,documented, and standardized
true
how many phases are in the DBLC?
6
DB initial study
DB design
implementation and loading
testing and evalution
operation
maintenance and evolution
what are the DB initial study’s overall purposes:
analyze company situation.
define problems and constraints
define objectives
define scope and boundries
t or f: interactive and iterative processes required to complete the second phase of DBLC successfully?
false
general conditions in which the company operates, its organizational structure, and its mission, this is the def of?
analyze the company situation
t or f: the goal of the analyzing the company situation is to discover what company’s operational components are,how they function, and how they interact?
true
defining problems and constraints are generated into three categories which are:
formal and informal information sources
finding precise answers is important
accurate problem definition does not always yield a situation.
t or f: database system objectives must correspond to those envisioned by middle users?
false
what are the Qs in the database’s initial study?
what is the proposed system’s initial objective?
will the system interface with other systems in the company?
will system share data with other systems or users?
the extent of design according to operational requirements. this is the def of?
scope
limits external to system. this is the def of?
boundaries
necessary to concentrate on data characteristics required to build Db model?
DB design
there are two views of data within system and they are?
business view
designer view
this business view is about data as an information source?
business view
this view is about data structure, access, and activity required to transform data into information?
designer view
actually implementing all design specifications from the previous phase. this is the def of which step?
implementation and loading
what are the steps of the implementation:
install DBMS
create database
load or convert the data
created logical representations of computing resources independent of physical resources. this is the def of?
virtualization
where do testing and evaluation occur?
in parallel with application programs
t or f: DB tools used to prototype applications?
true
if implementation fails to meet some system’s evaluation criteria, what should we do?
fine-tune specific to DBMS configuration parameters
modify physical or logical design
upgrade software or/and hardware platforms
what is being enforced via proper use of primary, foreign key rules?
integrity
types of backup and recovery after testing and evaluation:
full backup
differential backup
transaction backup
once a database has passed evaluation stage, it is considered an?
operational
t or f: the beginning of the operational phase starts the process of the system evolution
true
t or f: problems are forseen during testing surface?
false
solutions to the problems occurring in the operation phase include:
load-balancing software to distribute transactions amoung multiple computers
increase available cache
in which stage is it required periodic maintenance?
maintenance and evolution
t or f: preventing maintenance is for data recovery?
false
t or f: corrective is for data recovery ?
true
data modeling creates an abstract database structure. this is the def of?
conceptual design
t or f: conceptual design represents real world objects?
true
t or f: conceptual design doesn’t embody clear understanding of business and its funtional erea?
false
how many steps is it required for the conceptual design?
4
discover data element characteristics, this is the def of?
data analysis and requirements
t or f: data analysis obtain its characteristics from the same location?
false (different locations)
t or f: data analysis require thorough understanding of the company data types and their extent and uses?
true
t or f: data analysis takes into account business rules?
true
designer enforces standards in design documentation. this is the def of?
entity relationship modeling and normalization
designer enforces standards in design documentation. this is the def of?
entity relationship modeling and normalization
designer enforces standards in design documentation by?
use of diagram and symbols, documentation writing style, layout, other conventions
business rules must be incorporated into?
conceptual model
is a communications tool as well as a design blueprint?
ER model
verified against proposed system processes. this is the def of?
data model verification
revision of the original design by?
careful reevaluation of entities
detailed examination of attributes describing entities
information system components that handle specific functions, this is the def of?
module
portions of DB may reside in a different physical location. this is the def of?
distributed DB design
a subset of a DB stored at a given location. this is the def of?
DB fregment
t or f: distributed DB design processes accessing the database vary from one location to another?
true
t or f: the designer must also develop data distribution and allocation strategies?
true
critical to information system’s smooth operation. this is the def of?
DBMS software selection
common factors effecting purchasing decisions:
cost
DBMS features tools
underlying model
portability
DBMS hardware requirements
map conceptual design to a specific data model, this is the def of?
logical design
t or f: logical design still independent of physical-level details?
true
t or f: logical design translates software-independant conceptual model into software-dependant model
true
five mapping steps involve:
strong entities
supertype/subtype relationships
weak entities (dependant on strong entities)
binary relationship
higher degree relationships
t or f: all defined constraints must be supported by the logical data model?
true
translation requires the definition of the ……. domains and appropriate constraints?
attributes
t or f: all defined constraints must be supported by the logical data model
true
t or f: special attention should be placed at this stage to ensure security is enforce, may have to consider security restrictiond at the same location?
false, different location
all defined constrains must be supported by the logical data model. this is the def of?
the validate logical model integrity constrains
validate logical model integrity constrains is to ensure:
all views can be resolved
security is enforced to ensure the privacy of the data
final step in the logical design process?
validate the logical model against user requirements
t or f: in the final step, validate logical model definitions against all end-user data,transaction,and security requirements
true
process of selecting data storage and data access characteristics of the database. this is the def of:
physical design
storage characteristics are function of:
device types supported by hardware
types of data access methods supported by system
DBMS
t or f: physical design is more complex when data are distributed?
true
designer must determine several attributes, they are:
data volume
data usage patterns
define data storage organization in turn influence:
location and physical storage organization for each table
what indexes and types of indexes are to be used for each table
what views and the type views to be used on each table
set of database privileges that could be assigned as a unit to a user or group. this is the def of:
DB role
assign security controls by:
specific access rights on DB objects to a user or group of users
can also revoke during operation to assist with backups or maintenance events
performance can be affected by characteristics and they are:
storage media
seek time
sector and block size
and more
t or f: fine-tuning the DBMS and queries to ensure that they will meet end-user performance requirements?
true
chapter 4
t or f: relational DB model offers a logical view of data?
true
view data logically rather than physically. this is the def of?
relational model
structure and data independence. resembles a file collection. these are the the defs of?
table
t or f: relational database is harder to understand than hierarchal and network models?
false
t or f: logical view of relational DB is based on relation
true
t or f: relation is not the same as a table
false
two-dimensional structure composed of rows and columns, this is the def of?
table
t or f: table is a persistent representation of logical relation
true
t or f: a table contains group of related entities(entity set)?
true
t or f: each row in a table must be uniquely identifiable?
true
one or more attributes that determine other attributes, this is the def of?
key
what is a key role based on?
determination
t of f: if you know the value of attribute A, you can’t know the value of attribute B?
false
Attribute B is functionally dependent on A if all rows that agree in value A also agree on value B, this is the def if?
functional dependence
composed of more than one attribute. this is the def of?
composite key
any attribute that is a part of a key?
key attribute
any key that uniquely identifies each row?
super key
a super key without unnecessary attributes?
candidate key
each row in the table has its unique identity?
entity integrity
no data entry?
nulls
t or f: it is okay if there are nulls in other attributes?
false
nulls can represent :
an unknown attribute value
a known but missing attribute value
a not applicable condition
t or f: nulls can create logical problems when rational tables are linked?
true
makes the relational database work. this is the def of?
controlled redundancy
t or f: tables within the DB share common attributes?
true
t or f: redundancy exists only when there is unnecessary duplication of attributes values?
true
an attribute whose values match primary key values in the related table. this is the def of?
foreign key
foreign key contains a value that refers to an existing valid tuple in another relation?
referential integrity
key used strictly for data retrieval purposes?
secondary key
t or f: many relational DB management enforce integrity rules automatically.
true
why do designers use flags to avoid nulls?
flags indicate absence of some value
provide a detailed accounting of all tables found within the user/designer created DB. this is the def of?
data dictionary
t of f: data dictionary contain all attribute names characteristics for each table in the system and meta data?
true
what does system catalogs contain:
metadata
detailed system data dictionary that describes all objects within the database
indicates the use of the same name to label different attributes. this is the def of?
homonym
opposite of homonym?
synonym
the relational modeling idea?
1:m
and should be the norm in any relational DB design
should be rare in any relational DB design?
1:1
cant be implemented as such in the relational model?
m:n
can be changed to 1:M relationship
one entity related to only one other entity
sometimes means that entity components were not defined properly
could indicate that two entities actually belong in the same table
certain conditions absolutely require their use
1:1
implemented by breaking it up to produce a set of 1:M relationships
avoid problems inherent to M: N relationships by creating a composite entity; includes as foreign keys the primary keys of tables to be linked
the M:N relationships
t or f: data redundancy leads to data anomalies that can destroy the effectiveness of the DB?
true
control data redundancies by using common attributes shared by tables. this statement goes to the?
foreign key
t or f: sometimes. data redundancy is unnecessary?
false
