As per equivalence rules for query transformation, selection operation distributes over
Union.
Set difference.
Intersection.
All of the above.
Correct Answer :
D. All of the above.
Related Questions
The size of a data item is called its _______, which can be a field of some record or may be a larger unit such as a record.
Similarity
Granularity
Dimensionality
Arity
The relational model is based on the concept that data is organized and stored in two-dimensional tables called ______
Fields
Records
Relations
Keys
Which of the following is not comparison operator?
<>
<
=<
>=
What is a disjoint less constraint?
It requires that an entity belongs to no more than one level entity set.
The same entity may belong to more than one level.
The database must contain an unmatched foreign key value.
An entity can be joined with another entity in the same level entity set.
A relational database developer refers to a record as
an attribute
a tuple
a criteria
a relation
Relationships among relationships can be represented in an-E-R model using
Aggregation
Association
Weak entity sets
Weak relationship sets
In SQL, testing whether a subquery is empty is done using
DISTINCT
UNIQUE
NULL
EXISTS
The normalization was first proposed by .
Code
Codd
Boyce Codd
Boyce
What are the desirable properties of a decomposition
Partition constraint.
Dependency preservation.
Redundancy.
Security.
Wait-for graph is used for
detecting view serializability.
detecting conflict serializability.
deadlock prevention
deadlock detection
What will be the number of columns and rows respectively obtained for the operation, A- B, if A B are Base union compatible and all the rows of a are common to B? Assume A has 4 columns and 10 rows; and B has 4 columns and 15 rows
4,0
0,0
4,5
8,5
In an E-R, Y is the dominant entity and X is a subordinate entity. Then which of the following is incorrect :
Operationally, if Y is deleted, so is X
existence is dependent on Y.
Operationally, if X is deleted, so is Y.
Operationally, if X is deleted, & remains the same.
If the closure of an attribute set is the entire relation then the attribute set is a
superkey
candidate key
primary key
not a key
Which of the following is not a characteristic of a relational database model?
Table
Tree like structure
Complex logical relationship
Records
If an entity can belong to only one lower level entity then the constraint is
disjoint
partial
overlapping
single
Which of the following is not a property of transactions?
Atomicity
Concurrency
Isolation
Durability
In multiple granularity of locks SIX lock is compatible with
IX
IS
S
SIX
Relational Algebra is
Data Definition Language .
Meta Language
Procedural query Language
None of the above
Which of the following ensures the atomicity of the transaction?
Transaction management component of DBMS
Application Programmer
Concurrency control component of DBMS
Recovery management component of DBMS
Which of the following constitutes a basic set of operations for manipulating relational data?
Predicate calculus
Relational calculus
Relational algebra
SQL
Which one is true statement :
With finer degree of granularity of locking a high degree of concurrency is possible.
Locking prevents non-serializable schedules.
Locking cannot take place at field level.
An exclusive lock on data item X is granted even if a shared lock is already held on X.
DBMS is a collection of _____ that enables user to create and maintain a database.
Keys
Program
Translators
Language Activity
Protection of data from unauthorized Disclosure results in loss of _______
Integrity
Availability
Confidentiality
Discretionary Security
The fact that all employees of a particular organization should not have salaries more than $10000 is a _____ constraint.
Schema
Tuple
Domain
Relational
The part of a database management system which ensures that the data remains in a consistent state is
authorization and integrity manager
buffer manager
transaction manager
file manager
In a multi-user database, if two users wish to update the same record at the same time, they are prevented from doing so by
jamming
password
documentation
record lock
E-R Modeling is achieved by using ____ diagrams
DFD
Flowcharts
Gantt Charts
E-R
Which of the following statement on the view concept in SQL is invalid?
All views are not updateable
The views may be referenced in an SQL statement whenever tables are referenced.
The views are instantiated at the time they are referenced and not when they are defined.
The definition of a view should not have GROUP BY clause in it.
In E-R Diagram total participation is represented by
Double lines
Single line
Dashed lines
Triangle
Given the following relation S(SNO,SNAME,CITY) write a query to update the value of CITY to KANPUR for the supplier S1.
UPDATE S CITY = KANPUR WHERE SNO=S1
UPDATE S SET CITY = KANPUR FOR SNO=S1
UPDATE S SET CITY = KANPUR WHERE SNO=S1
UPDATE S RENAME CITY = KANPUR WHERE SNO=S1