Welcome!

Industrial IoT Authors: Dalibor Siroky, Elizabeth White, Stackify Blog, Yeshim Deniz, SmartBear Blog

Related Topics: Industrial IoT

Industrial IoT: Article

SimpleType and ComplexType in a Schema

Designing your own

This tutorial discusses the simpleType and complexType XML Schema structures and their corresponding representations in an XML document. XML Schema is used as the basis of an XML document structure, and some of the XML technologies, such as JAXB, are based on XML Schema.

Overview
An XML Schema is an XML-based representation of the structure of an XML document. XML Schema supports data types and namespaces; a DTD does not. In this tutorial, the simpleType and complexType structures used to represent a XML document will be discussed.

SimpleType Declaration
SimpleTypes are custom data types used with element and attribute declarations. A simpleType is represented with a <xs:simple Type/> declaration. An <xs:simpleType/> element is used to constrain character data in a element or a attribute declaration. A simpleType is used to constrain data types only; a simpleType does not have attributes or element nodes. With an element declaration the simpleType is used as:

<xs:schema>
<xs:element name="A" type="simpleTypeA"/>
<xs:simpleType name="simpleTypeA">
</xs:simpleType>
</xs:schema>

or

<xs:element name="A">
<xs:simpleType>
</xs:simpleType>
</xs:element>

With an attribute declaration, the simpleType is used as

<complexType> <xs:attribute name="AttributeA" type="simpleTypeA"/> </complexType>

or

<xs:attribute name="AttributeA">
<xs:simpleType>
</xs:simpleType>
<xs:attribute>

The <xs:simpleType/> declaration may be present in an <xs:element/> element, <xs:attribute/> element, <xs:restriction/> element, <xs:list/> element, <xs:union/> element, or the <xs:schema/> element.

The <xs:simpleType/> element may contain one of the <xs:restriction/>, <xs:list/>, <xs:union/> elements.

SimpleType with Restriction Element
A simpleType used to constrain a decimal data type would be

<xs:element name="A">
<xs:simpleType>
<xs:restriction base="xs:decimal">
<xs:minExclusive value="1.0"/>
<xs:maxInclusive value="5.0"/>
<xs:totalDigits value="3"/>
<xs:fractionDigits value="2"/>
</xs:restriction>
</xs:simpleType>
</xs:element>

A corresponding representation of element Element "A" in an XML document would be

<A>5.0</A>

Element "A" in an XML document may have values between 2.00 and 5.00 (inclusive). Declaration <A>1.0</A> or <A>25.0</A> would not validate with the Schema.

A simpleType to constrain the length of a string data type would be

<xs:element name="A">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:minLength value="5"/>
<xs:maxLength value="10"/>
</xs:restriction>
</xs:simpleType>
</xs:element>

A corresponding representation of "A" in an XML document would be

<A>string</A>
Declaration <A>str</A>

or

<A>stringelement</A>

would not validate with the Schema.

An element with a fixed length would be represented with simpleType as

<xs:element name="A">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:length value="5"/>
</xs:restriction>
</xs:simpleType>
</xs:element>

An example of a corresponding representation of ?A? in an XML document would be

<A>strin</A>

An attribute with an enumeration of values would be represented with simpleType as


     <xs:element name="A" >
       <xs:complexType>
         <xs:attribute
          name="AttributeA">
           <xs:simpleType>
             <xs:restriction
              base="xs:string">
               <xs:enumeration
                value="a"/>
               <xs:enumeration
                value="b"/>
              </xs:restriction>
            </xs:simpleType>
          </xs:attribute>
        </xs:complexType>
      </xs:element>

A corresponding representation in an XML document is

<A AttributeA="a"/>

"AttributeA" may have one of the values, "a" or "b."

The <xs:restriction/> element in a <xs:simpleType/> may be used to constrain the value space of data types derived from the string data type with the <xs:whitespace/> element.

The whiteSpace element is represented as <xs:whiteSpace value="preserve|collapse|replace"/>. The value of the attribute "value" of element <xs:whitespace/> may be "preserve," "collapse," or "replace."

If the value of an attribute "value" is "preserve," the whitepaces in the string data type are not changed. If the value of the attribue "value" is "replace," all occurrences of #x9(tab), #xA(linefeed), and #xD(carriage return) are replaced with a #x20(space).

An element with a whiteSpace restriction on its string value is represented in a schema as

<xs:element name="A">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:whiteSpace value="replace"/>
<xs:restriction>
</xs:simpleType>
</xs:elementA>

If the value of attribute "value" is "replace," the string in "A" in an XML document represented as

<A> Trim
      String
WhiteSpace</A>

would be parsed as "Trim String White Space."

If the value of the attribute '"value" is "collapse," the leading and trailing #x20(space) are removed, and contiguous occurances of #x20(space) are merged into a single #x20(space).

If the value of the attribute "value" is "collapse," the string in "A" in an XML document represented as

<A> Trim String WhiteSpace </A>

would be parsed as "Trim String White Space".

<xs:restriction/> element <xs:pattern/> is used to constrain the value space of data types to literals which match a regular expression.

An example of a simpleType with pattern restriction would be

<xs:element name="A">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:pattern value="[1-5]{2}(-[5-10]{3})"/>
</xs:simpleType>
</xs:element>

An example of a corresponding representation in a XML document is

<A>25-567</A>

SimpleType with List Element
A simpleType may be used to represent a list of values in a XML document element with

<xs:list/> element.
<xs:element name="A">
<xs:simpleType>
<xs:list itemType="xs:decimal"/>
</xs:simpleType>
</xs:element>

An element with a list of values would be

<A>1.0 2 3</A>

SimpleType with Union Element
A simpleType may be used to represent a union of simpleTypes with the <xs:union/> element.

<xs:element name="A">
<xs:simpleType>
<xs:union>
<xs:simpleType>
<xs:restriction base="xs:integer"/>
</xs:simpleType>
<xs:simpleType>
<xs:restriction base="xs:string"/>
</xs:simpleType>
</xs:union>
</xs:simpleType>
</xs:element>

An element with a union of simpleTypes in an XML document would be

<A>15</A>

or

<A>element A</A>

"A" may be either an integer or a string.

ComplexType Declaration
A complexType is used to constrain elements and attributes in an XML document. It is represented with <xs:complex Type/>.

A complexType declaration may occur in the <xs:schema/> declaration or a <xs:element/> declaration.

If a complexType is declared in the <xs:schema/> element, the complexType may be referred to in the ?type? attribute of an element declaration.

<xs:schema>
<complexType name="complexTypeA">
</complexType>
<xs:element name="A" type="complexTypeA"/>
</xs:schema>

A text(PCDATA) element is represented with a complexType as


     <xsd:element name="A">
      <xsd:complexType mixed="true">
        <xsd:complexContent>
          <xsd:restriction
           base="xsd:anyType">
          </xsd:restriction>
        </xsd:complexContent>
      </xsd:complexType>
    </xsd:element>

The corresponding representation of a text element in an XML document is

<A>Text Element</A>

An empty element is represented with a complexType as


    <xsd:element name="A">
      <xsd:complexType mixed="false">
        <xsd:complexContent>
          <xsd:restriction
           base="xsd:anyType">
          </xsd:restriction>
        </xsd:complexContent>
      </xsd:complexType>
    </xsd:element>

The corresponding representation of an empty element in an XML document is <A/>.

An unordered element set is represented with a complexType element as


    <xs:element name="A" >
      <xs:complexType>
        <xs:all>
          <xs:element name="B"
           type="xs:string"/>
          <xs:element name="C"
           type="xs:string"/>
          <xs:element name="D"
           type="xs:string"/>
        </xs:all>
      </xs:complexType>
    </xs:element>

A corresponding representation of an unordered element set in an XML document is

<A>
<D>Element D</D>
<B>Element B</B>
<C>Element C</C>
</A>

An element with a choice and a sequence is represented with a complex Type as


    <xs:element name="A" >
      <xs:complexType>
        <xs:sequence>
          <xs:choice>
          <xs:element name="B"
           type="xs:string"/>
          <xs:element name="C"
           type="xs:string"/>
          </xs:choice>
          <xs:element name="D"
           type="xs:string"/>
         </xs:sequence>
        </xs:choice>
      </xs:complexType>
    </xs:element>

A corresponding representation of an element with a choice and sequence in a XML document is

<A>
<B>Element B</B>
<D>Element D</D>
</A>

ComplexType with Mixed Content
An element with a mixed content is represented in a complexType as


    <xs:element name="A" >
      <xs:complexType mixed="true">
        <xs:element name="B"
         type="xs:string"/>
    </xs:complexType>
   </xs:element>

The corresponding representation of a mixed content element in an XML document is

<A>Element Text
<B>Element B</B>
</A>

ComplexType with SimpleContent Element
Elements with character data and attributes are represented with the <xs:simpleContent/> element.


<xs:element name="A">
<xs:complexType>
 <xs:simpleContent>
  <xs:extension base="xs:string">
   <xs:attribute name="attr"
    type="xs:integer"/>
  </xs:extension>
 </xs:simpleContent>
</xs:complexType>
</element>

The corresponding representation of a simpleContent element in a XML document is

<A attr="15">simpleContent Type Element</A>

The simpleContent element may also be used with the <xs:restriction/> element.


<xs:element name="A">
<xs:complexType>
 <xs:simpleContent>
  <xs:restriction base="xs:string">
  <xs:minLength value="5"/>
   <xs:attribute name="a"
    type="xs:integer"/>
  </xs:restriction>
 </xs:simpleContent>
</xs:complexType>
</element>

The corresponding representation of a simpleContent element with a restriction in a XML document is

<A a="15">Element A</A>

ComplexType with ComplexContent Element
An element with constraint on its elements and attributes may be represented with the <xs:complexContent/> element. An example of this element would be

<xs:element name="A">
<xs:complexType>
<xs:complexContent>
<xs:restriction base="anyType">
<xs:sequence>
<xs:element name="B" type="xs:string"/>
<xs:element name="C" type="xs:integer"/>
</xs:sequence>
</xs:restriction>
</xs:complexContent>
</xs:complexType>
</xs:element>

The corresponding representation of element ?A? with complexContent in a XML document is

<A><B>Element B</B><C>25</C></A>

The complexContent element may be used to extend another complexType.

<xs:complexType name="complexTypeA">
<xs:sequence>
<xs:element name="B"/>
<xs:element name="C"/>
</xs:sequence>
</xs:complexType>
<xs:element name="A">
<xs:complexType>
<xs:complexContent>
<xs:extension base="complexTypeA">
<xs:sequence>
<xs:element name="D"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
</xs:element>

The corresponding representation of a complexContent element with an extension on another complexType is

<A>
<B>Element B</B>
<C>Element C</C>
<D>Element D</D>
</A>

Conclusion
This tutorial discussed the simpleType and complexType XML Schema structures, which may be used to design custom simpleType and complexType elements.

Resources:

  • XML Schema: Structures Specification.
  • More Stories By Deepak Vohra

    Deepak Vohra is a Sun Certified Java 1.4 Programmer and a Web developer.

    More Stories By Ajay Vohra

    Ajay Vohra is a senior solutions architect with DataSynapse Inc.

    Comments (0)

    Share your thoughts on this story.

    Add your comment
    You must be signed in to add a comment. Sign-in | Register

    In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


    @ThingsExpo Stories
    In his session at 21st Cloud Expo, Carl J. Levine, Senior Technical Evangelist for NS1, will objectively discuss how DNS is used to solve Digital Transformation challenges in large SaaS applications, CDNs, AdTech platforms, and other demanding use cases. Carl J. Levine is the Senior Technical Evangelist for NS1. A veteran of the Internet Infrastructure space, he has over a decade of experience with startups, networking protocols and Internet infrastructure, combined with the unique ability to it...
    "There's plenty of bandwidth out there but it's never in the right place. So what Cedexis does is uses data to work out the best pathways to get data from the origin to the person who wants to get it," explained Simon Jones, Evangelist and Head of Marketing at Cedexis, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
    "Cloud Academy is an enterprise training platform for the cloud, specifically public clouds. We offer guided learning experiences on AWS, Azure, Google Cloud and all the surrounding methodologies and technologies that you need to know and your teams need to know in order to leverage the full benefits of the cloud," explained Alex Brower, VP of Marketing at Cloud Academy, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clar...
    Large industrial manufacturing organizations are adopting the agile principles of cloud software companies. The industrial manufacturing development process has not scaled over time. Now that design CAD teams are geographically distributed, centralizing their work is key. With large multi-gigabyte projects, outdated tools have stifled industrial team agility, time-to-market milestones, and impacted P&L stakeholders.
    Gemini is Yahoo’s native and search advertising platform. To ensure the quality of a complex distributed system that spans multiple products and components and across various desktop websites and mobile app and web experiences – both Yahoo owned and operated and third-party syndication (supply), with complex interaction with more than a billion users and numerous advertisers globally (demand) – it becomes imperative to automate a set of end-to-end tests 24x7 to detect bugs and regression. In th...
    "Akvelon is a software development company and we also provide consultancy services to folks who are looking to scale or accelerate their engineering roadmaps," explained Jeremiah Mothersell, Marketing Manager at Akvelon, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
    "MobiDev is a software development company and we do complex, custom software development for everybody from entrepreneurs to large enterprises," explained Alan Winters, U.S. Head of Business Development at MobiDev, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
    SYS-CON Events announced today that CrowdReviews.com has been named “Media Sponsor” of SYS-CON's 22nd International Cloud Expo, which will take place on June 5–7, 2018, at the Javits Center in New York City, NY. CrowdReviews.com is a transparent online platform for determining which products and services are the best based on the opinion of the crowd. The crowd consists of Internet users that have experienced products and services first-hand and have an interest in letting other potential buye...
    "IBM is really all in on blockchain. We take a look at sort of the history of blockchain ledger technologies. It started out with bitcoin, Ethereum, and IBM evaluated these particular blockchain technologies and found they were anonymous and permissionless and that many companies were looking for permissioned blockchain," stated René Bostic, Technical VP of the IBM Cloud Unit in North America, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Conventi...
    SYS-CON Events announced today that Telecom Reseller has been named “Media Sponsor” of SYS-CON's 22nd International Cloud Expo, which will take place on June 5-7, 2018, at the Javits Center in New York, NY. Telecom Reseller reports on Unified Communications, UCaaS, BPaaS for enterprise and SMBs. They report extensively on both customer premises based solutions such as IP-PBX as well as cloud based and hosted platforms.
    "Space Monkey by Vivent Smart Home is a product that is a distributed cloud-based edge storage network. Vivent Smart Home, our parent company, is a smart home provider that places a lot of hard drives across homes in North America," explained JT Olds, Director of Engineering, and Brandon Crowfeather, Product Manager, at Vivint Smart Home, in this SYS-CON.tv interview at @ThingsExpo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
    Coca-Cola’s Google powered digital signage system lays the groundwork for a more valuable connection between Coke and its customers. Digital signs pair software with high-resolution displays so that a message can be changed instantly based on what the operator wants to communicate or sell. In their Day 3 Keynote at 21st Cloud Expo, Greg Chambers, Global Group Director, Digital Innovation, Coca-Cola, and Vidya Nagarajan, a Senior Product Manager at Google, discussed how from store operations and ...
    It is of utmost importance for the future success of WebRTC to ensure that interoperability is operational between web browsers and any WebRTC-compliant client. To be guaranteed as operational and effective, interoperability must be tested extensively by establishing WebRTC data and media connections between different web browsers running on different devices and operating systems. In his session at WebRTC Summit at @ThingsExpo, Dr. Alex Gouaillard, CEO and Founder of CoSMo Software, presented ...
    WebRTC is great technology to build your own communication tools. It will be even more exciting experience it with advanced devices, such as a 360 Camera, 360 microphone, and a depth sensor camera. In his session at @ThingsExpo, Masashi Ganeko, a manager at INFOCOM Corporation, introduced two experimental projects from his team and what they learned from them. "Shotoku Tamago" uses the robot audition software HARK to track speakers in 360 video of a remote party. "Virtual Teleport" uses a multip...
    A strange thing is happening along the way to the Internet of Things, namely far too many devices to work with and manage. It has become clear that we'll need much higher efficiency user experiences that can allow us to more easily and scalably work with the thousands of devices that will soon be in each of our lives. Enter the conversational interface revolution, combining bots we can literally talk with, gesture to, and even direct with our thoughts, with embedded artificial intelligence, whic...
    SYS-CON Events announced today that Evatronix will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Evatronix SA offers comprehensive solutions in the design and implementation of electronic systems, in CAD / CAM deployment, and also is a designer and manufacturer of advanced 3D scanners for professional applications.
    Leading companies, from the Global Fortune 500 to the smallest companies, are adopting hybrid cloud as the path to business advantage. Hybrid cloud depends on cloud services and on-premises infrastructure working in unison. Successful implementations require new levels of data mobility, enabled by an automated and seamless flow across on-premises and cloud resources. In his general session at 21st Cloud Expo, Greg Tevis, an IBM Storage Software Technical Strategist and Customer Solution Architec...
    To get the most out of their data, successful companies are not focusing on queries and data lakes, they are actively integrating analytics into their operations with a data-first application development approach. Real-time adjustments to improve revenues, reduce costs, or mitigate risk rely on applications that minimize latency on a variety of data sources. In his session at @BigDataExpo, Jack Norris, Senior Vice President, Data and Applications at MapR Technologies, reviewed best practices to ...
    An increasing number of companies are creating products that combine data with analytical capabilities. Running interactive queries on Big Data requires complex architectures to store and query data effectively, typically involving data streams, an choosing efficient file format/database and multiple independent systems that are tied together through custom-engineered pipelines. In his session at @BigDataExpo at @ThingsExpo, Tomer Levi, a senior software engineer at Intel’s Advanced Analytics gr...
    When talking IoT we often focus on the devices, the sensors, the hardware itself. The new smart appliances, the new smart or self-driving cars (which are amalgamations of many ‘things’). When we are looking at the world of IoT, we should take a step back, look at the big picture. What value are these devices providing? IoT is not about the devices, it’s about the data consumed and generated. The devices are tools, mechanisms, conduits. In his session at Internet of Things at Cloud Expo | DXWor...