XQuery Interview Questions

XQuery Interview Questions

Here, questions and answers which have been asked in other companies are offered to XQuery interview. Let's see a sample of key issues from the XQuery interview.

1. What is XQuery?

XQuery is an XML query language that is case sensitive and was developed to query XML details. This is the same as with database tables for SQL. XQuery is used for recovery of XML file data.

Example: Suppose we need to find out the list of students in an XML file located in a given area. XQuery will solve queries of this type.

2. Explain the syntax rules for XQuery.

A description of the fundamental guidelines for XQuery syntaxes:

• XQuery is sensitive to the case.
• Attributes and variables that we've used in XQuery components will have clear XML names.
• XQuery can be written of single and double quotations.
• The variables XQuery should be set to $(variable name). For instance: A $book.
• Can write XQuery comment between colon (:). Like:: (XQuery Comments:)

3. How to define functions in XQuery?

XML has a number of built in features. XQuery functions of string values, numeric values, date and time relations, Boolean values usually do.

4. In which year XQuery first appeared?

XQuery emerged first in 2007. It was developed by W3C, and on January 23, 2007, it became the W3C recommendation. XQuery 3.0 is an 8 April 2014 W3C Recommendation.

5. What is the use of XQuery language?

XQuery is a functional language in which items and attributes are identified and extracted from XML documents. Any use of the language in XQuery is as follows:

• Retrieve hierarchical as well as tabular data.
• To query tree structures as well as graphical models.
• Creating Web pages.
• For Internet pages to be queried.
• Transforming XML documents into XHTML.
• Good for the databases and object-oriented applications focused on XML. Databases on artifacts are far more flexible and efficient than purely tabular databases.

6. What do you mean by XQuery FLWOR?

FLWOR is an acronym that stands for "Return for, Let, When, Order by."

For-Collection of a list of nodes is required.

Let-Used for binding a sequence to a variable.

Where-For sampling the nodes.

Order by-Used for grouping the nodes.

Return-Specifies when to return (gets checked once per every node).

7. What is the syntax of XQuery language?

The XQuery language elements, attributes, and variables must be correct XML terms, which must be sensitive to the case.

8. What is the difference between XQuery and XSLT?

• XQuery is guided by program whereas XSLT is driven by document.
• Although XQuery is declarative, XSLT is functional
• XSLT is in XML, although XQuery is not in XML.

9. What type of queries can the XQuery solve?

The following queries in XML data can be solved through XQuery:

• XQuery is used in Web service to retrieve information.
• The summary report is generated using this.
• It's used for converting XML to XHTML data.
• It can be used when we want any important Web page information.

10. What is selecting and filtering element in XQuery?

Selecting and filtering apply to the database query to select a data category and filter the data for a specific type. For instance to select the name of books whose price is less than $50? The term XQuery FLWOR and Path are used to find and search the XML components. These are used to select the appropriate elements and filter them away.

for $a in doc("bookmart.xml")/bookstore/book  
where $a/price<250  
order by $a/title  
return $a/title 

11. What is the difference between XQuery and XPath?

XQuery is the practical language for programming and querying while XPath is the language for the XML path.

XQuery is used to retrieve and interpret data from either XML documents or relational databases, while XPath is used to compute values from certain XML documents such as strings, numbers and boolean types.

12. How to perform conditional operations in XQuery?

If-Then-Else is process which is conditional in XQuery. Let's go? Consider an example to see if you can do it:

for $a in doc("bookmart.xml")/bookstore/book  
return  if ($a/@category="BOOKS")  
then <child>{data($a/title)}</child>  
else <adult>{data($a/title)}</adult>  

13. What do you mean by XQuery add?

XQuery add is used to add elements, attributes, HTML items and text to the input application output results.

14. What is the use of current-date() function in XQuery?

The current day feature of XQuery is used to retrieve the latest date.

15. How to use XQuery FLWOR with HTML?

If you choose to put HTML item with XQuery FLWOR, you can add and tag the expression FLWOR.

<ul>    
{    
for $x in doc("courses.xml")/bookstore/book/title    
order by $x    
return <li>{$x}</li>    
}    
</ul>   

16. What are the uses of time and date function in XQuery?

In XQuery, the feature time and date is used to provide the time and date. XQuery comprises three types of time and date functions:

• current-date()
• current-time()
• current-datetime()

17. What is meant by the word ?node? in XQuery?

That element inside the XML document shall be regarded as a node.

18. What is the use of current-time() function in XQuery?

The current-time XQuery function is used to provide the current time.

19. What is the use of current-datetime() function in XQuery?

The method XQuery current-date time() is used to display the current date and time.

20. How many kinds of nodes are there in XQuery?

The XQuery mentioned below described mainly seven types of nodes available:

• Comment
• Element
• Namespace
• Attribute
• Text
• Document (root) node
• Processing-instruction

21. What are the different types of XQuery functions?

A list of different types of XQuery functions:

• Duration/Date/Time Functions
• Boolean Functions
• Accessor Functions
• Numeric Functions
• AnyURI Functions
• Node Functions
• String Functions
• Sequence Functions
• Context Functions
• QName Functions
• Error and Trace Functions

22. What do you mean by atomic values in XQuery?

Atomic values apply to nodes that have no parents and children.

23. Explain the relationship of different nodes in XQuery?

Parent: Every attribute and element has one parent node.

Children: The Node of Elements increasing have none, one or more members.

Siblings: Siblings apply to nodes that have the same node as parents.

Ancestors: Members of a parent node ... etc.

Descendants: The children of a node .... etc.

24. What is the difference between XPath expressions and FLWOR expressions in XQuery?

Path and FLWOR are also capable of querying the XML file, but differently. In XPath language, we can define the node to be extracted from the XML document along with a condition to be filled in for XML document fetch. Of eg, a situation may be of any type because we choose to show the names of the books whose price is less than thirty dollars. Such a condition can apply to expressions in XPath.

And in the FLWOR expression as the name implies 'F' 'L' 'O' 'R' refers to 'for' 'Let' 'Where' 'Order by' 'Return.' Where Return is necessary and the rest of the elements such as 'for' 'Let' 'Where' 'Order by' are optional.

25. Write a syntax to demonstrate the use of FLWOR expression in XQuery.

for $x in doc("courses123.xml")/bookshop/book
where $x/price>120
order by $x/category
return $x/category

26. What is meant by for clause in XQuery?

For clause, binding a variable to each item returned by expression is used within the expression FLWOR. The same expression can include one or more 'for' provisions.

27. What is meant by the order by clause in XQuery?

In the FLWOR expression, order by clause is used to arrange the return value through the phrase FLWOR either in ascending or descending order, or alphabetically. In FLWOR, order by clause is optional.

28. Which clause is compulsory in XQuery and why?

It is necessary to include a return clause in the FLWOR expression since the primary purpose of the query is to select any data.