Data Table XML Encoding

This appendix describes how Data Tables are encoded into (and decoded from) XML. Data Tables are XML-encoded only when they have to be transferred as String arguments for Web Service functions, in all other cases Iotellect uses its own encoding syntax.

In most other components of Iotellect (Database, Iotellect Communications Protocol etc.) Data Tables are stored and transferred using so-called native encoding. This format is covered in a separate appendix.

XML Schema for Data Tables

Below is the XML Schema used to encode Data Tables:

An XML schema is a description of a type of XML document, typically expressed in terms of constraints on the structure and content of documents of that type, above and beyond the basic syntax constraints imposed by XML itself. An XML schema provides a view of the document type at a relatively high level of abstraction.

For more information, see http://www.w3.org/XML/Schema.

<?xml version="1.0" encoding="UTF-8"?>

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">

<xs:element name="table">

       <xs:complexType>

               <xs:sequence>

                       <xs:element ref="format" minOccurs="0" maxOccurs="1"/>

                       <xs:element ref="records" minOccurs="0" maxOccurs="1"/>

               </xs:sequence>

       </xs:complexType>

</xs:element>

<xs:element name="format">

       <xs:complexType>

               <xs:sequence>

                       <xs:element ref="fields" minOccurs="0"/>

               </xs:sequence>

               <xs:attribute name="maxRecords" type="xs:integer"/>

               <xs:attribute name="minRecords" type="xs:integer"/>

       </xs:complexType>

</xs:element>

<xs:element name="fields">

       <xs:complexType>

               <xs:sequence>

                       <xs:element ref="field" maxOccurs="unbounded"/>

               </xs:sequence>

       </xs:complexType>

</xs:element>

<xs:element name="field">

       <xs:complexType>

               <xs:sequence>

                       <xs:element ref="selectionValues" minOccurs="0"/>

                       <xs:element ref="defaultValue" minOccurs="0"/>

               </xs:sequence>

               <xs:attribute name="description"/>

               <xs:attribute name="name" type="xs:NCName" use="required"/>

               <xs:attribute name="notReplicated" type="xs:boolean"/>

               <xs:attribute name="nullable" type="xs:boolean"/>

               <xs:attribute name="readonly" type="xs:boolean"/>

               <xs:attribute name="type" type="fieldType" use="required"/>

       </xs:complexType>

</xs:element>

<xs:element name="selectionValues">

       <xs:complexType>

               <xs:sequence>

                       <xs:element ref="option" maxOccurs="unbounded"/>

               </xs:sequence>

       </xs:complexType>

</xs:element>

<xs:element name="option">

       <xs:complexType mixed="true">

               <xs:complexContent>

                       <xs:extension base="fieldVal">

                               <xs:attribute name="description" use="required"/>

                       </xs:extension>

               </xs:complexContent>

       </xs:complexType>

</xs:element>

<xs:element name="defaultValue" type="fieldVal"/>

<xs:element name="records">

       <xs:complexType>

               <xs:sequence>

                       <xs:element ref="record" maxOccurs="unbounded"/>

               </xs:sequence>

       </xs:complexType>

</xs:element>

<xs:element name="record">

       <xs:complexType>

               <xs:sequence>

                       <xs:element name="value" maxOccurs="unbounded" minOccurs="0">

                           <xs:complexType mixed="true">

                               <xs:complexContent>

                                               <xs:extension base="fieldVal">

                                                       <xs:attribute name="name" use="required"/>

                                               </xs:extension>

                                       </xs:complexContent>

                           </xs:complexType>

                       </xs:element>

               </xs:sequence>

       </xs:complexType>

</xs:element>

<xs:simpleType name="fieldType">

       <xs:restriction base="xs:string">

               <xs:enumeration value="A"/>

               <xs:enumeration value="I"/>

               <xs:enumeration value="D"/>

               <xs:enumeration value="T"/>

               <xs:enumeration value="S"/>

               <xs:enumeration value="B"/>

               <xs:enumeration value="L"/>

               <xs:enumeration value="F"/>

               <xs:enumeration value="O"/>

               <xs:enumeration value="C"/>

       </xs:restriction>

</xs:simpleType>

<xs:complexType name="fieldVal" mixed="true">

       <xs:choice minOccurs="0">

               <xs:element ref="data"/>

               <xs:element ref="table"/>

       </xs:choice>

</xs:complexType>

<xs:element name="data">

       <xs:complexType>

               <xs:attribute name="name" type="xs:string"/>

               <xs:attribute name="contentType" type="xs:string"/>

       </xs:complexType>

</xs:element>

</xs:schema>

This XML Schema defines the structure of a Data Table XML document. The root element is table, corresponding to a whole Data Table.

The table element may contain one format element which describes the Data Table's format. It may also contain optional records element that encapsulates a list of table records with the data itself.

The format element must include a fields sub-element containing a list of table fields. It can have minRecords and maxRecords attributes that define a minimum and maximum number of records in the table. If minRecords is not defined, the minimal number of records is zero. If maxRecords is not defined, the maximal number of records is unlimited (limited by 2^64 in practice).

The fields element consists of one or more field elements. A field element defines the format of a single field. It requires name and type attributes. The fieldType element can be represented by one of the type code characters defined here. description, notReplicated, nullable and readonly attributes are optional. field element can also include selectionValues and defaultValue sub-elements. More these attributes and elements may be found in the Data Tables article.

The selectionValues element can contain one or more option elements. A value element is of fieldVal type. value element has required description attribute that  specifies description of a certain selection value.

defaultValue is also of fieldVal type.

Elements of fieldVal type are used to store data values of table cells, selection values and default value. Elements of this type may be represented by:

  • table elements (nested tables)
  • data elements (binary data blocks)
  • simple text content (all other types of values, see encoding rules here)

The records element contains a sequence of record elements. Each record represents a single Data Table record. It contains a number of value elements. Their data type is fieldVal, described above. Each element also has a required name attribute indicating the name of the field whose value is represented by the value.

Example of a Data Table Encoded in XML Format

<?xml version="1.0" encoding="UTF-8"?>

<table xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <!-- Data Table -->

<format maxRecords="1" minRecords="1"> <!-- Table Format Descriptor -->

       <fields> <!-- Field Set -->

               <field description="Username" name="username" notReplicated="true" readonly="true" type="S"/>

               <field description="First Name" name="firstname" notReplicated="true" nullable="true" type="S"/>

               <field description="Last Name" name="lastname" notReplicated="true" nullable="true" type="S"/>

               <field description="Password" name="password" notReplicated="true" type="S"/>

               <field description="Country" name="country" type="I">

                       <selectionValues>

                               <option description="Albania">1</option>

                               <option description="Algeria">2</option>

                               -- skipped --

                       </selectionValues>

               </field>

               <field description="Region/State/Province/Area" name="region" nullable="true" type="S"/>

               <field description="ZIP Code" name="zip" nullable="true" type="S"/>

               <field description="City" name="city" nullable="true" type="S"/>

               <field description="Address 1" name="address1" nullable="true" type="S"/>

               <field description="Address 2" name="address2" nullable="true" type="S"/>

               <field description="Comments" name="comments" nullable="true" type="S"/>

               <field description="Company" name="company" nullable="true" type="S"/>

               <field description="Department" name="department" nullable="true" type="S"/>

               <field description="E-mail Address" name="email" notReplicated="true" nullable="true" type="S"/>

               <field description="Phone No." name="phone" notReplicated="true" nullable="true" type="S"/>

               <field description="Fax No." name="fax" notReplicated="true" nullable="true" type="S"/>

               <field description="Time Zone" name="timezone" type="S">

                       <selectionValues>

                               <option description="GMT-12:00, Etc/GMT+12">Etc/GMT+12</option>

                               <option description="GMT-11:00, Etc/GMT+11">Etc/GMT+11</option>

                               -- skipped --

                       </selectionValues>

                       <defaultValue>Europe/Moscow</defaultValue>

               </field>

               <field description="Locale" name="locale" type="S">

                       <selectionValues>

                               <option description="Default"/>

                               <option description="aa">aa</option>

                               <option description="ab">ab</option>

                               -- skipped --

                       </selectionValues>

                       <defaultValue>en</defaultValue>

               </field>

               <field description="Date Pattern" name="datepattern" type="S"/>

               <field description="Time Pattern" name="timepattern" type="S"/>

               <field description="Enable Automatic Registration of Device Servers" name="dsautoregistration" type="B"/>

       </fields>

</format>

<records> <!-- Data Table Records -->

       <record> <!-- First Record -->

               <value name="username">ronnie</value>

               <value name="firstname">Ronnie</value>

               <value name="lastname">O'Sullivan</value>

               <value name="password">11111</value>

               <value name="country">218</value>

               <value name="datepattern">dd.MM.yyyy</value>

               <value name="timepattern">HH:mm:ss</value>

               <value name="dsautoregistration">1</value>

       </record>

       <record> <!-- Second Record -->

               <value name="username">john</value>

               <value name="firstname">John</value>

               <value name="lastname">Doe</value>

               <value name="password">12345</value>

               <value name="country">83</value>

               <value name="datepattern">dd.MM.yyyy</value>

               <value name="timepattern">HH:mm:ss</value>

               <value name="dsautoregistration">1</value>

       </record>

</records>

</table>

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