XML VS JSON

XML

.Data interchange format

.Extensible Markup Language:

• Text-based, self describing data presentation
• Meta language (i.e. use this language to define your own data structure)

.Platform independent

.Widely supported

.Specified by W3C for the World Wide Web

XML Basics I

      .XML is based on markup

                    ∘Opening and closing tags

                               <tag>…</tag>

      ∙A tag has …

                           ∘… a name

                         

∘… optional content between opening and closing tag

                           ∘… an optional namespace

                           ∘… optional attributes

                           <tag key=“value”>…</tag>

XML Example

              <book bookid="1234">

              <title>XML in 5 minutes</title>

              <author>T.Knowsitall</author>

              <price>0.50</price>

              <availability>1</availability>

              <bookoftheyear/>

              </book>

XML Basics II

            ∙XML documents must be well-formed

                      ∘Begin with the XML declaration

                                  <?xml version="1.0"?>

                     ∘Have one unique root element

                     ∘All start tags must match end tags (case sensitive)

                     ∘All elements must be closed

                     ∘All elements must be properly nested

                     ∘All attribute values must be quoted

                     ∘XML entities must be used for special characters

                           •e.g. &lt; for <

XML Structure

  ∙XML document: elements in a hierarchical structure

           ∘XML is good at encoding tree structures

  ∙Structure somewhat evident for humans

           ∘Only syntax, semantics left for guessing

           ∘Verbose text representation

  ∙How to encode arbitrary graphs in XML?

          ∘E.g. a graph with circular references?

XML Validation

  ∙XML documents can be validated

        ∘Predefine structure of a document

        ∘Check if document matches structure

  ∙1. DTDs (Document Type Definitions)

        ∘Extended context-free grammar

        ∘Part of XML specification – not covered here

  ∙2. XML schema

        ∘Define structure of a document in XML

        ∘Support for data types (built-in and user-defined)

XML Schema Example

           <element name="book">

                <attribute name="bookid" type="decimal"/>

                    <complexType>

                        <sequence>

                          <element name="title" type="string"/>

                          <element name="author" type="string"/>

                          <element name="price" type="string"/>

                          <element name="availability" type="string"/>

                          <element name="bookoftheyear" minOccurs="0" maxOccurs="1"/>

                       </sequence>

                   </complexType>

             </element>

APIs for Using XML

   ∙How to read data from an XML document?

   ∙Document Object Model (DOM)

           ∘Parses XML as tree into memory

           ∘Easy traversal via API (e.g. go to child element)

   ∙Simple API for XML (SAX)

           ∘Throws events for each XML element (e.g. here comes a tag, here comes an attribute,   etc.)

           ∘Not „simple“ to use at all

   ∙XPath & XPointer: address elements in document

XPath / XPointer

   ∙XPath: Language for accessing XML elements

           ∘The Root element: /*

           ∘The fifth child element under an element named "FOOB": FOOB[5]

           ∘The element FOOB whose BAZ attribute is equal to

               “hello":

                FOOB[ @BAZ = “hello" ]

   ∙XPointer: another language, e.g.

           ∘<foobar id="foo"><bar/><baz><bom/></baz></foobar>

           ∘element(foo/2/1)

XML Summary

   ∙Meta language for defining other languages

             ∘i.e. data structure in your application

   ∙Data interchange format

             ∘Breaks documents into hierarchical parts

             ∘Gives the parts names

             ∘Lets you write rules for how parts form a document

   ∙Inefficient

             ∘Expensive conversion from binary data to text

             ∘Text format uses lot of space

XML Myths

   ∙XML is simple

   ∙XML is human-readable

   ∙Proof: MS Word  Save  Unpack  XML

JavaScript Object Notation (JSON)

   ∙Data interchange format
   ∙Originates from JavaScript for Web usage
            ∘But has been also implemented for other programming languages
   ∙Text format like XML
            ∘But no query languages unlike XML
   ∙Convert data object to JSON & send

            ∘Receive & parse JSON to data object

JSON Example
   {
        "bookid": 1234,
        "title": "JSON in 5 minutes",
        "author": "T.Knowsitall",
        "price": 0.50,
        "availability": 1,
        "bookoftheyear": true,

     }

JSON Data Types
∙Numbers: (un)signed integer, float/double
∙String
∙Boolean
∙Array
∘"someArray": [ 1, 2, 3, 4 ]
∙Object (key/value map)
∘{ "foo": "bar", "moep": { "nested": "structure" } }
∙null

XML vs. JSON

∙JSON is simpler and easier than XML
∙XML has more features
∘Query languages
∘Document transformation via XSLT
∘Validation via XML Schema
∙Both are text formats

∘JSON slightly less verbose

For Further more study go to this https://www.w3schools.com/
                                                      https://www.json.org/
Follow me on....

Twitter: UsmanAzmat87
Facebook: Musman.azmat
Linkedln: osman-khan-633180106/
Google+: u/0/102433731988304229241