CS 6400 Exam 3 STUDY
QUESTIONS AND VERIFIED
CORRECT ANSWERS
GRADED A+ [LATEST] 100%
GUARANTEED PASS
minimal cover - CORRECT ANSWER-E is a minimal set of dependencies that is equivalent to E . a
set of dependencies in a standard or canonical form and with no redundancies.
universal relation assumption - CORRECT ANSWER-states that every attribute name is unique
D (decomposition ) - CORRECT ANSWER-is called a decomposition of R. decompose the
universal relation schema R into a set of relation schemas D = {R1, R2, ... , Rm} that will become
the relational database schema
attribute preservation - CORRECT ANSWER-make sure that each attribute in R will appear in at
least one relation schema Ri in the decomposition so that no attributes are lost
dependency preserving - CORRECT ANSWER-union of the projections of F on each Ri in D is
equivalent to F; that is, ((πR1(F)) ∪ K ∪ (πRm(F)))+ = F+.
projection of F on Ri, - CORRECT ANSWER-πRi(F) where Ri is a subset of R, is the set of
dependencies X → Y in F+ such that the attributes in X ∪ Y are all contained in Ri
,lossless joins guarantee - CORRECT ANSWER-the join filed must be a key in at least one of the
relations
lossless - CORRECT ANSWER-refers to loss of information, not to loss of tuples
counterexample - CORRECT ANSWER-a relation state r of R that satisfies the dependencies in F
but does not satisfy the nonadditive join condition.
-proves that D does not have the nonadditive join property with respect to F.
Binary Decomposition - CORRECT ANSWER-—decomposition of a relation R into two relations
Primary storage - CORRECT ANSWER-provides fast access to data but is of limited storage
capacity. can be operated on directly by the computer's central processing unit (CPU)
Secondary storage - CORRECT ANSWER-magnetic disks
flash memories
solid-state drive (SSD)
Tertiary storage - CORRECT ANSWER-Optical disks (CD-ROMs, DVDs, and other similar storage
media).
Data in secondary or tertiary storage cannot be processed directly by the CPU
cache memory - CORRECT ANSWER-a static RAM (random access memory); used by the CPU to
speed up execution of program using techniques such as prefetching and pipelining
main memory - CORRECT ANSWER-main work area for the CPU for keeping program
instructions and data; RAM is volatile, fast, small and expensive
, DRAM - CORRECT ANSWER-Programs reside and execute in dynamic random-access memory
main memory databases - CORRECT ANSWER-entire databases can be kept in main memory
(with a backup copy on magnetic disk)
flash memory - CORRECT ANSWER-fast access speed, high-density, high-performance
memories, using EEPROM (electrically erasable programmable read-only memory) technology.
Between DRAM and magnetic disk storage, another form of memor
Optical Drives - CORRECT ANSWER-CDs (compact disks) and DVDs
Optical jukebox memories - CORRECT ANSWER-use an array of CD-ROM platters, which are
loaded onto drives on demand.
Tertiary Storage - CORRECT ANSWER-type of computer storage device that typically consists of
magnetic tape (HDD, etc. )
magnetic tapes - CORRECT ANSWER-are used for archiving and backup storage of data.
Tape jukeboxes - CORRECT ANSWER-popular as tertiary storage to hold terabytes of data
Persistent Data - CORRECT ANSWER-data that must persist over long periods of time; accessed
and processed repeatedly during the storage period.
transient data - CORRECT ANSWER-persists for only a limited time during program execution
volatile storage - CORRECT ANSWER-main memory
QUESTIONS AND VERIFIED
CORRECT ANSWERS
GRADED A+ [LATEST] 100%
GUARANTEED PASS
minimal cover - CORRECT ANSWER-E is a minimal set of dependencies that is equivalent to E . a
set of dependencies in a standard or canonical form and with no redundancies.
universal relation assumption - CORRECT ANSWER-states that every attribute name is unique
D (decomposition ) - CORRECT ANSWER-is called a decomposition of R. decompose the
universal relation schema R into a set of relation schemas D = {R1, R2, ... , Rm} that will become
the relational database schema
attribute preservation - CORRECT ANSWER-make sure that each attribute in R will appear in at
least one relation schema Ri in the decomposition so that no attributes are lost
dependency preserving - CORRECT ANSWER-union of the projections of F on each Ri in D is
equivalent to F; that is, ((πR1(F)) ∪ K ∪ (πRm(F)))+ = F+.
projection of F on Ri, - CORRECT ANSWER-πRi(F) where Ri is a subset of R, is the set of
dependencies X → Y in F+ such that the attributes in X ∪ Y are all contained in Ri
,lossless joins guarantee - CORRECT ANSWER-the join filed must be a key in at least one of the
relations
lossless - CORRECT ANSWER-refers to loss of information, not to loss of tuples
counterexample - CORRECT ANSWER-a relation state r of R that satisfies the dependencies in F
but does not satisfy the nonadditive join condition.
-proves that D does not have the nonadditive join property with respect to F.
Binary Decomposition - CORRECT ANSWER-—decomposition of a relation R into two relations
Primary storage - CORRECT ANSWER-provides fast access to data but is of limited storage
capacity. can be operated on directly by the computer's central processing unit (CPU)
Secondary storage - CORRECT ANSWER-magnetic disks
flash memories
solid-state drive (SSD)
Tertiary storage - CORRECT ANSWER-Optical disks (CD-ROMs, DVDs, and other similar storage
media).
Data in secondary or tertiary storage cannot be processed directly by the CPU
cache memory - CORRECT ANSWER-a static RAM (random access memory); used by the CPU to
speed up execution of program using techniques such as prefetching and pipelining
main memory - CORRECT ANSWER-main work area for the CPU for keeping program
instructions and data; RAM is volatile, fast, small and expensive
, DRAM - CORRECT ANSWER-Programs reside and execute in dynamic random-access memory
main memory databases - CORRECT ANSWER-entire databases can be kept in main memory
(with a backup copy on magnetic disk)
flash memory - CORRECT ANSWER-fast access speed, high-density, high-performance
memories, using EEPROM (electrically erasable programmable read-only memory) technology.
Between DRAM and magnetic disk storage, another form of memor
Optical Drives - CORRECT ANSWER-CDs (compact disks) and DVDs
Optical jukebox memories - CORRECT ANSWER-use an array of CD-ROM platters, which are
loaded onto drives on demand.
Tertiary Storage - CORRECT ANSWER-type of computer storage device that typically consists of
magnetic tape (HDD, etc. )
magnetic tapes - CORRECT ANSWER-are used for archiving and backup storage of data.
Tape jukeboxes - CORRECT ANSWER-popular as tertiary storage to hold terabytes of data
Persistent Data - CORRECT ANSWER-data that must persist over long periods of time; accessed
and processed repeatedly during the storage period.
transient data - CORRECT ANSWER-persists for only a limited time during program execution
volatile storage - CORRECT ANSWER-main memory
