Xml Ques & Ans

What is the difference between SAX parser and DOM parser? DOM parser - reads the whole XML document and returns a DOM tree representation of xml document. It provides a convenient way for reading, analyzing and manipulating XML files. It is not well suited for large xml files, as it always reads the whole file before processing. SAX parser - works incrementally and generate events that are passed to the application. It does not generate data representation of xml content so some programming is required. However, it provides stream processing and partial processing which cannot be done alone by DOM parser. What is Xpath? XPath is used to navigate through elements and attributes in an XML document. What is XSL? XSLT - a language for transforming XML documents XSLT is used to transform an XML document into another XML document, or another type of document that is recognized by a browser, like HTML and XHTML. Normally XSLT does this by transforming each XML element into an (X)HTML element. A DTD is: The XML Document Type Declaration contains or points to markup declarations that provide a grammar for a class of documents. This grammar is known as a document type definition or DTD. The DTD can point to an external subset containing markup declarations, or can contain the markup declarations directly in an internal subset, or can even do both. A Schema is: XML Schemas express shared vocabularies and allow machines to carry out rules made by people. They provide a means for defining the structure, content and semantics of XML documents. In summary, schemas are a richer and more powerful of describing information than what is possible with DTDs. What is XML Namespace? The XML namespaces recommendation defines a way to distinguish between duplicate element type and attribute names. Such duplication might occur, for example, in an XSLT stylesheet or in a document that contains element types and attributes from two different DTDs. An XML namespace is a collection of element type and attribute names. The namespace is identified by a

unique name, which is a URI. Thus, any element type or attribute name in an XML namespace can be uniquely identified by a two-part name: the name of its XML namespace and its local name. This two-part naming system is the only thing defined by the XML namespaces recommendation. 1. What is the difference between SAX parser and DOM parser? DOM spec defines an object-oriented hieararchy. The DOM parser creates an internal tree based on the hierarchy of the XML data. Tree stays in memory until released. The DOM parser is more memory intensive. DOM Parser’s advantage is that it is simple. Pairs nicely with XSLT. SAX spec defines an event based approach, calling handler functions whenever certain text nodes or processing instructions are found. These events include the start and end of the document, finding a text node, finding child elements, and hitting a malformed element. SAX development is more challenging. SAX can parse gigabytes worth of XML without hitting resource barriers. It’s also faster and more complex. Better for huge XML docs. Best suited for sequential-scan applications. 2. What is the difference between Schema and DTD? Schema might outphase DTD. XML shemas are in XML. XML Schema has a lot of built-in data types including xs:string,xs:decimal,xs:integer,xs:boolean,xs:date,xs:time. XML schemas can be edited with Schema files, parsed with XML parser, manipulated with XML DOM, and transformed with XSLT. The building blocks of DTD include elements, attributes, entities, PCDATA, and CDATA. 3. How do you parse/validate the XML document? By using a SAXParser, DOMParser, or XSDValidator. 4. What is XML Namespace? Defining a namespace to avoid confusion involves using a prefix and adding an xmlns attribute to the tag to give the prefix a qualified name associated with the namespace. All child elements with the same prefix are associated with the namespace defined in the start tag of an element. 5. What is Xpath? XPath is a language for addressing parts of an XML document, designed to be used by both XSLT and XPointer. 6. What is XML template? * A style sheets describes transformation rules * A transformation rule: a pattern + a template * Pattern: a configuration in the source tree * Template: a structure to be instantiated in the result tree * When a pattern is matched in the source tree, the corresponding pattern is generated in the result tree 7. How would you produce PDF output using XSL’s? FOP it. =) -transform xml into xsl-fo doc using xslt, or DOM or SAX -process xsl-fo using a Formatter to convert xsl-fo into a pdf.

8. What are the steps to transform XML into HTML using XSL? An XSLT processor may output the result tree as a sequence of bytes.The xsl:output element allows stylesheet authors to specify how they wish the result tree to be output. If an XSLT processor outputs the result tree, it should do so as specified by the xsl:output element; however, it is not required to do so.The method attribute on xsl:output identifies the overall method that should be used for outputting the result tree. 9. What is XSL? In addition to XSLT, XSL includes an XML vocabulary for specifying formatting. XSL specifies the styling of an XML document by using XSLT to describe how the document is transformed into another XML document that uses the formatting vocabulary. 10. What is XSLT? A language for transforming XML documents into other XML documents. XSLT is designed for use as part of XSL, which is a stylesheet language for XML.