In SQL the statement select * from R, S is equivalent to
Select * from R natural join S.
Select * from R cross join S.
Select * from R union join S.
Select * from R inner join S.
Correct Answer :
B. Select * from R cross join S.
Related Questions
For correct behaviour during recovery, undo and redo operation must be
Commutative
Associative
idempotent
distributive
DBMS helps achieve
Centralized control of data
Data independence
Both A and B
Neither A nor B
Which of the following is not a consequence of non-normalized database?
Update Anomaly
Insertion Anomaly
Redundancy
Lost update problem
Which of the following concurrency control schemes is not based on the serializability property?
Two - phase locking
Graph-based locking
Time-stamp based locking
None of these .
Relational Algebra does not have
Selection operator.
Projection operator.
Aggregation operators.
Division operator.
Isolation of the transactions is ensured by
Transaction management
Application programmer
Concurrency control
Recovery management
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 .
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
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.
The cost of reading and writing temporary files while evaluating a query can be reduced by
building indices
pipelining
join ordering
none of the above
______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
Between DRAM and magnetic disk storage another form of memory, called ______ memory is becoming common because it is non volatile.
RAM
Flash
Hard Disk
Secondary
Which of the following relational algebra operations do not require the participating tables to be union-compatible?
Union
Intersection
Difference
Join
Grant and revoke are _____ statements.
TCL
DCL
DDL
DML
DROP is a statement in SQL.
Query
Embedded SQL
DDL
DCL
Which of the syntax is correct for insert statement?
i) insert into values
ii) insert into (column list) values
ii) insert into
i-only
ii-only
Both of them
None of them
The transactions like adding an employee, enrolling a student in a course are examples of _______
Logical
Physical
None
Theoretical
Relations produced from an E-R model will always be
First normal form.
Second normal form.
Third normal form.
Fourth normal form.
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.
Wait-for graph is used for
detecting view serializability.
detecting conflict serializability.
deadlock prevention
deadlock detection
Which one is correct statement?
Logical data independence provides following without changing application programs:
(i) Changes in access methods.
(ii) Adding new entities in database
(iii) Splitting an existing record into two or more records
(iv) C
(i) and (ii)
(iv) only
(i) and (iv)
(ii) and (iii)
______is a preferred method for enforcing data integrity
Constraints
Triggers
Stored procedure
Cursors
Which of the following is not a consequence of concurrent operations?
Lost update problem.
Update anomaly.
Unrepeatable read.
Dirty read.
Whenever two independent one-to-many relationships are mixed in the same relation, a __________ arises.
Functional dependency
Multi-valued dependency
Transitive dependency
Partial dependency
The drawback of shadow paging technique are
Commit overhead
Data fragmentation
Garbage collection
All of these
The normalization was first proposed by .
Code
Codd
Boyce Codd
Boyce
The relational model is based on the concept that data is organized and stored in two-dimensional tables called ______
Fields
Records
Relations
Keys
In 2NF
No functional dependencies (FDs) exist.
No multivalued dependencies (MVDs) exist.
No partial FDs exist.
No partial MVDs exist.
If an entity can belong to only one lower level entity then the constraint is
disjoint
partial
overlapping
single
The statement that is executed automatically by the system as a side effect of the modification of the database is
backup
assertion
recovery
trigger