CS6400 PROCTORED TEST BANK LATEST
WITH ACTUAL QUESTIONS AND CORRECT
VERIFIED ANSWERS GRADED A PLUS 100
PERCENT GUARANTEED PASS
◉implementation (or physical storage) level . Answer: how the tuples in
a base relation are stored and updated
◉bottom-up design methodology . Answer: (also called design by
synthesis) considers the basic relationships among individual attributes
as the starting point and uses those to construct relation schemas
◉top-down design methodology . Answer: (also called design by
analysis) starts with a number of groupings of attributes into relations
that exist together naturally
◉measures to determine the quality of relation schema design . Answer:
■ Making sure that the semantics of the attributes is clear in the schema
■ Reducing the redundant information in tuples
■ Reducing the NULL values in tuples
■ Disallowing the possibility of generating spurious tuples
,◉semantics of a relation . Answer: refers to its meaning resulting from
the interpretation of attribute values in a tuple
◉update anomalies . Answer: can be classified into insertion anomalies,
deletion anomalies, and modification anomalies
◉Insertion Anomalies . Answer: occur when users attempt to store an
attribute value in the system but they cannot because the value of
another unnecessary but required attribute is not known
◉Deletion Anomalies . Answer: occur when a value for one attribute
that users wish to keep is unexpectedly removed when a value for
another attribute is deleted
◉Modification Anomalies . Answer: occur when changes to multiple
instances of an entity (rows of a table) are needed to effect an update to a
single value of an attribute
◉Spurious tuples . Answer: Tuples generated by joining two relations
on attributes that are not keys or foreign keys on these relations.
◉Waste of storage space . Answer: due to NULLs and the difficulty of
performing selections, aggregation operations, and joins due to NULL
values
,◉A functional dependency (A->B) . Answer: occurs when the attribute
A uniquely determines B. A = left-hand side, B=right-hand-side.
-is a property of the semantics or meaning of the attributes.
◉FD or f.d. . Answer: abbreviation for functional dependency
◉Candidate Key . Answer: An attribute, or combination of attributes,
that uniquely identifies a row in a relation.
◉legal relation states (or legal extensions) of R . Answer: Relation
extensions r(R) that satisfy the functional dependency constraints
◉FD cannot be inferred automatically . Answer: must be defined
explicitly by someone who knows the semantics of the attributes of R.
◉diagrammatic notation . Answer: isplaying FDs: Each FD is displayed
as a horizontal
◉Normalization of Data . Answer: a process of analyzing the given
relation schemas based on their FDs and primary keys to achieve the
desirable properties of (1) minimizing redundancy and (2) minimizing
the insertion, deletion, and update anomalies
, ◉Boyce-Codd Normal Form (BCNF) . Answer: A special type of third
normal form (3NF) in which every determinant is a candidate key. A
table in BCNF must be in 3NF.
◉normal form test . Answer: is decomposed into smaller relation
schemas that contain a subset of the attributes and meet the test that was
otherwise not met by the original relation.
◉nonadditive join . Answer: or lossless join property, guarantees that
the spurious tuple generation problem does not occur
◉dependency preservation property . Answer: ensures that each
functional dependency is represented in some individual relation
resulting after decomposition
◉superkey . Answer: any key that uniquely identifies each row
◉key . Answer: of a relation schema R = {A1, A2, ... , An} is a set of
attributes S ⊆ R with the property that no two tuples t1 and t2 in any
legal relation state r of R will have t1[S] = t2[S].
◉Candidate Key . Answer: An attribute, or combination of attributes,
that uniquely identifies a row in a relation.
WITH ACTUAL QUESTIONS AND CORRECT
VERIFIED ANSWERS GRADED A PLUS 100
PERCENT GUARANTEED PASS
◉implementation (or physical storage) level . Answer: how the tuples in
a base relation are stored and updated
◉bottom-up design methodology . Answer: (also called design by
synthesis) considers the basic relationships among individual attributes
as the starting point and uses those to construct relation schemas
◉top-down design methodology . Answer: (also called design by
analysis) starts with a number of groupings of attributes into relations
that exist together naturally
◉measures to determine the quality of relation schema design . Answer:
■ Making sure that the semantics of the attributes is clear in the schema
■ Reducing the redundant information in tuples
■ Reducing the NULL values in tuples
■ Disallowing the possibility of generating spurious tuples
,◉semantics of a relation . Answer: refers to its meaning resulting from
the interpretation of attribute values in a tuple
◉update anomalies . Answer: can be classified into insertion anomalies,
deletion anomalies, and modification anomalies
◉Insertion Anomalies . Answer: occur when users attempt to store an
attribute value in the system but they cannot because the value of
another unnecessary but required attribute is not known
◉Deletion Anomalies . Answer: occur when a value for one attribute
that users wish to keep is unexpectedly removed when a value for
another attribute is deleted
◉Modification Anomalies . Answer: occur when changes to multiple
instances of an entity (rows of a table) are needed to effect an update to a
single value of an attribute
◉Spurious tuples . Answer: Tuples generated by joining two relations
on attributes that are not keys or foreign keys on these relations.
◉Waste of storage space . Answer: due to NULLs and the difficulty of
performing selections, aggregation operations, and joins due to NULL
values
,◉A functional dependency (A->B) . Answer: occurs when the attribute
A uniquely determines B. A = left-hand side, B=right-hand-side.
-is a property of the semantics or meaning of the attributes.
◉FD or f.d. . Answer: abbreviation for functional dependency
◉Candidate Key . Answer: An attribute, or combination of attributes,
that uniquely identifies a row in a relation.
◉legal relation states (or legal extensions) of R . Answer: Relation
extensions r(R) that satisfy the functional dependency constraints
◉FD cannot be inferred automatically . Answer: must be defined
explicitly by someone who knows the semantics of the attributes of R.
◉diagrammatic notation . Answer: isplaying FDs: Each FD is displayed
as a horizontal
◉Normalization of Data . Answer: a process of analyzing the given
relation schemas based on their FDs and primary keys to achieve the
desirable properties of (1) minimizing redundancy and (2) minimizing
the insertion, deletion, and update anomalies
, ◉Boyce-Codd Normal Form (BCNF) . Answer: A special type of third
normal form (3NF) in which every determinant is a candidate key. A
table in BCNF must be in 3NF.
◉normal form test . Answer: is decomposed into smaller relation
schemas that contain a subset of the attributes and meet the test that was
otherwise not met by the original relation.
◉nonadditive join . Answer: or lossless join property, guarantees that
the spurious tuple generation problem does not occur
◉dependency preservation property . Answer: ensures that each
functional dependency is represented in some individual relation
resulting after decomposition
◉superkey . Answer: any key that uniquely identifies each row
◉key . Answer: of a relation schema R = {A1, A2, ... , An} is a set of
attributes S ⊆ R with the property that no two tuples t1 and t2 in any
legal relation state r of R will have t1[S] = t2[S].
◉Candidate Key . Answer: An attribute, or combination of attributes,
that uniquely identifies a row in a relation.
