Use of UNIQUE while defining an attribute of a table in SQL means that the attribute values are
distinct values
cannot have NULL
both (A) & (B)
same as primary key
Correct Answer :
C. both (A) & (B)
Related Questions
A relational database developer refers to a record as
an attribute
a tuple
a criteria
a relation
Grant and revoke are _____ statements.
TCL
DCL
DDL
DML
A data type or format is specified for each _________
Relation
Tuple
Database
Domain
DBMS is a collection of _____ that enables user to create and maintain a database.
Keys
Program
Translators
Language Activity
Use of UNIQUE while defining an attribute of a table in SQL means that the attribute values are
distinct values
cannot have NULL
both (A) & (B)
same as primary key
______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
In SQL the word natural can be used with
inner join
full outer join
right outer join
all of the above
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.
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.
Processed data is called _____
Raw data
Source
Information
Useful data
Which of the following is not a characteristic of a relational database model?
Table
Tree like structure
Complex logical relationship
Records
In an ER model,_____ is described in the database by storing its data.
Entity
Attribute
Relationship
Notation
Which of the following is not a consequence of concurrent operations?
Lost update problem.
Update anomaly.
Unrepeatable read.
Dirty read.
If two relations R and S are joined, then the non matching tuples of both R and S are ignored in
left outer join
right outer join
full outer join
inner join
In 2NF
No functional dependencies (FDs) exist.
No multivalued dependencies (MVDs) exist.
No partial FDs exist.
No partial MVDs exist.
The values of the attribute describes a particular
Entity set
File
Entity instance
Organization
operator is used to compare a value to a list of literals values that have been specified.
Like
COMPARE
BETWEEN
IN
Cascading rollback is avoided in all protocol except
strict two-phase locking protocol.
tree locking protocol
two-phase locking protocol
validation based protocol.
In b-tree the number of keys in each node is than the number of its children.
one less
same
one more
half
Immediate database modification technique uses
Both undo and redo.
Undo but no redo.
Redo but no undo.
Neither undo nor redo.
_______ product was acquired by Informix, integrated into its RDBMS and introduced as the Informix Universal Server an ORDBMS.
Star
llustar
SQL
Cygnus
_____ command can be used to modify a column in a table
alter
update
set
create
According to the levels of abstraction, the schema at the intermediate level is called
Logical schema.
Physical schema.
Subschema.
None of the above.
The clause in SQL that specifies that the query result should be sorted in ascending or descending order based on the values of one or more columns is
View
Order by
Group by
Having
Assume transaction A holds a shared lock R. If transaction B also requests for a shared lock on R.
It will result in a deadlock situation.
It will immediately be rejected.
It will immediately be granted.
It will be granted as soon as it is released by A .
Create a table with the following attributes: Employee(EMPNO integer, EMPNAME of 10 characters)
Create table Employee(EMPNO int, EMPNAME char(10));
Create table Employee(EMPNO integer, EMPNAME String(10));
Create table Emplo(EMPNO number, EMPNAME string);
Create table Emp(EMPNO int, EMPNAME char(10));
The transactions like adding an employee, enrolling a student in a course are examples of _______
Logical
Physical
None
Theoretical
An advantage of views is
Data security
Derived columns
Hiding of complex queries
All of the above
An advantage of the database management approach is
data redundancy increases
data is dependent on programs
data is integrated and can be accessed by multiple programs
none of the above
_____clause is an additional filter that is applied to the result.
Select
Order by
Group-by
Having