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4

In SQL the statement select * from R, S is equivalent to

A. Select * from R natural join S.

B. Select * from R cross join S.

C. Select * from R union join S.

D. Select * from R inner join S.

Correct Answer :

B. Select * from R cross join S.


Related Questions

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4

Use of UNIQUE while defining an attribute of a table in SQL means that the attribute values are

A. distinct values

B. cannot have NULL

C. both (A) & (B)

D. same as primary key

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4

Relational Algebra is

A. Data Definition Language .

B. Meta Language

C. Procedural query Language

D. None of the above

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4

Which normal form is considered adequate for normal relational database design?

A. 2NF

B. 5NF

C. 4NF

D. 3NF

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4

In an ER model,_____ is described in the database by storing its data.

A. Entity

B. Attribute

C. Relationship

D. Notation

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4

Which of the following is not a consequence of non-normalized database?

A. Update Anomaly

B. Insertion Anomaly

C. Redundancy

D. Lost update problem

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4

In SQL, testing whether a subquery is empty is done using

A. DISTINCT

B. UNIQUE

C. NULL

D. EXISTS

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4

Union operator is a :

A. Unary Operator

B. Ternary Operator

C. Binary Operator

D. Not an operator

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4

The one guideline to be followed while designing the database is

A. A database design may be ambiguous.

B. It should avoid/reduce the redundancy.

C. Unrelated data should be in the same table so that updating the data will be easy.

D. An entity should not have attributes.

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4

Relations produced from an E-R model will always be

A. First normal form.

B. Second normal form.

C. Third normal form.

D. Fourth normal form.

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4

A table can have only one

A. Secondary key

B. Alternate key

C. Unique key

D. Primary key

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4

The common column is eliminated in

A. theta join

B. outer join

C. natural join

D. composed join

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4

An advantage of views is

A. Data security

B. Derived columns

C. Hiding of complex queries

D. All of the above

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4

If an entity can belong to only one lower level entity then the constraint is

A. disjoint

B. partial

C. overlapping

D. single

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4

What is a disjoint less constraint?

A. It requires that an entity belongs to no more than one level entity set.

B. The same entity may belong to more than one level.

C. The database must contain an unmatched foreign key value.

D. An entity can be joined with another entity in the same level entity set.

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4

Manager salary details are hidden from the employee .This is

A. Conceptual level data hiding.

B. External level data hiding.

C. Physical level data hiding.

D. None of these.

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4

Which of the following is a reason to model data?

A. Understand each user's perspective of data

B. Understand the data itself irrespective of the physical representation

C. Understand the use of data across application areas

D. All of the above

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4

The ____ operator joins two or more conditions and displays rows only if that rows data satisfies all conditions specified.

A. OR

B. AND

C. NOT

D. ALL

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4

Shadow paging has

A. no redo

B. no undo

C. redo but no undo

D. neither redo nor undo

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4

SQL server stores index information in the _____system table

A. system indexes

B. syst indexes

C. sys indexes

D. sysind

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4

The default level of consistency in SQL is

A. repeatable read

B. read committed

C. read uncommitted

D. serializable

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4

______contains information that defines valid values that are stored in a column or data type.

A. Default

B. Index

C. Rule

D. View

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4

Which of the following concurrency control schemes is not based on the serializability property?

A. Two - phase locking

B. Graph-based locking

C. Time-stamp based locking

D. None of these .

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4

A list consists of last names, first names, addresses and pin codes. If all people in the list have the same last name and same pin code a useful key would be

A. the pin code

B. the last name

C. the compound key first name and last name

D. Tr from next page

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4

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

A. View

B. Order by

C. Group by

D. Having

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4

In SQL the statement select * from R, S is equivalent to

A. Select * from R natural join S.

B. Select * from R cross join S.

C. Select * from R union join S.

D. Select * from R inner join S.

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4

_______ product was acquired by Informix, integrated into its RDBMS and introduced as the Informix Universal Server an ORDBMS.

A. Star

B. llustar

C. SQL

D. Cygnus

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4

A weak entity has an ______ dependency on its owner entity, which can be used for both ON UPDATE and ON DELETE.

A. Direct

B. Indirect

C. Existence

D. No

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4

Create a table with the following attributes: Employee(EMPNO integer, EMPNAME of 10 characters)

A. Create table Employee(EMPNO int, EMPNAME char(10));

B. Create table Employee(EMPNO integer, EMPNAME String(10));

C. Create table Emplo(EMPNO number, EMPNAME string);

D. Create table Emp(EMPNO int, EMPNAME char(10));

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4

Which of the following statement on the view concept in SQL is invalid?

A. All views are not updateable

B. The views may be referenced in an SQL statement whenever tables are referenced.

C. The views are instantiated at the time they are referenced and not when they are defined.

D. The definition of a view should not have GROUP BY clause in it.

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4

In E-R Diagram total participation is represented by

A. Double lines

B. Single line

C. Dashed lines

D. Triangle