A ____ key specifies a uniqueness constraint that no two distinct tuples in any state r of relation R can have the same value for super key.
Sub
Parent
Candidate
Super
Correct Answer :
D. Super
Related Questions
______is a special type of integrity constraint that relates two relations & maintains consistency across the relations.
Domain Integrity Constraints
Referential Integrity Constraints
Domain Constraints
Entity Integrity Constraints
A _____ is used to define overall design of the database
code
data definition language
application program
schema
Which of the following is not a property of transactions?
Atomicity
Concurrency
Isolation
Durability
Which of the following is not comparison operator?
<>
<
=<
>=
DFD stands for
Data Flow Document
Data File Diagram
Data Flow Diagram
Non of the above
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.
DROP is a statement in SQL.
Query
Embedded SQL
DDL
DCL
Cascading rollback is avoided in all protocol except
strict two-phase locking protocol.
tree locking protocol
two-phase locking protocol
validation based protocol.
In an ER model,_____ is described in the database by storing its data.
Entity
Attribute
Relationship
Notation
Key to represent relationship between tables is called
primary key
secondary key
foreign key
none of the above
By ______ an area on disk in certain ways, one can make it represent a bit value of either zero (0) or one (1).
Vulcanizing
Galvanizing
Magnetizing
Passing UV rays
Which of the following is not a logical database structure?
Chain
Network
Tree
Relational
The data models defined by ANSI/SPARC architecture are
Conceptual, physical and internal
Conceptual, view and external
Logical, physical and internal
Logical, physical and view
The rule that a value of a foreign key must appear as a value of some specific table is called a
Referential constraint.
Index.
Integrity constraint.
Functional dependency.
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.
operator is used to compare a value to a list of literals values that have been specified.
Like
COMPARE
BETWEEN
IN
In a relational schema, each tuple is divided into fields called
Relations
Queries
Domains
All of the above
Which of the following relational algebra operations do not require the participating tables to be union-compatible?
Union
Intersection
Difference
Join
Consider the join of relation R with a relation S. If R has m tuples and S has n tuples, then the maximum and minimum size of the join respectively are
m+n and 0
m+n and |m-n|
mn and 0
mn and m+n
In an ER diagram the ___shape specifies the Attibute and a ____ shape specifies the primary key attribute.
Oval; An oval with an underlined attribute
Circle; A circle with bolded attribute inside it
Diamond; A bolded attribute
Square; An attribute within the square
In b-tree the number of keys in each node is than the number of its children.
one less
same
one more
half
For correct behaviour during recovery, undo and redo operation must be
Commutative
Associative
idempotent
distributive
Grant and revoke are _____ statements.
TCL
DCL
DDL
DML
A data type or format is specified for each _________
Relation
Tuple
Database
Domain
Which of the following is not a consequence of non-normalized database?
Update Anomaly
Insertion Anomaly
Redundancy
Lost update problem
The metadata is created by the
DML compiler
DML pre-processor
DDL interpreter
Query interpreter
The common column is eliminated in
theta join
outer join
natural join
composed join
_____clause is an additional filter that is applied to the result.
Select
Order by
Group-by
Having
Employees in a company are each assigned their own office, i.e. for each employee there exists a unique office and for each office there exists a unique employee; This statement is an example of ____ type of relation.
1:1
1: Many
Many: One
Many : Many
As per equivalence rules for query transformation, selection operation distributes over
Union.
Set difference.
Intersection.
All of the above.