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A namespace uniquely identifies a Web service and is specified by the <targetNamespace> element in the WSDL that represents the service. A data service is simply a Web service with specialized functionality. As a data service implementation is based on XML, namespace handling is an important aspect to it. 

When developing a data service, you get to specify namespaces in several places as followsData services are implemented using XML, which means that there can be conflicting element names. Therefore, we use namespaces to uniquely identify the elements defined within a specific web service. Using namespaces for a data service is optional. However, in certain data services, namespaces become necessary. Read below for more information.

See the following topics for instructions on setting namespaces at different levels of a data service:

Setting the namespace for a data service

The service namespace is used to uniquely identify a web service, which means that this namespace applies to all elements in the data service. In the WSDL which that represents the service, it the namespace is indicated by the "targetNamespace" attribute of the WSDL document element. The service namespace can be set using the  Create/Edit Data Service window of the Data Services Server management console.

For example,

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Data service result row namespace

This namespace is set through the Row namespace value in the query result section. It associates the result rows or result entries of a specific namespace. Therefore, all the subelements in that result raw are under this namespace by default.

when you define a data service using the management console as shown below.

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Setting the namespace for a data service query

When you define a query for your data service, you can set a namespace for the elements in the query result (output mapping). That is, the Row Namespace applies to all the result rows that you define as output mappings for that query. The example below shows how the row namespace is set for the query result element: Customers.

After setting the row namespace, the Customers element's data type of the Customers element falls under the given namespace as shown below.

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The XML Schema fragment in data types section taken from the service's WSDL is as follows:

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Namespaces for specific elements in the result

<query id="employeesByNumberSQL" useConfig="default">
      <sql>select * from Employees where employeeNumber = ?</sql>
      <result defaultNamespace="http://abc.com/empNamespace1" element="employees" rowName="employee">
         <element column="lastName" name="last-name" xsdType="string"/>
         <element column="firstName" name="first-name" xsdType="string"/>
         <element column="email" name="email" xsdType="string"/>
         <element column="salary" name="salary" xsdType="double"/>
      </result>
      <param name="employeeNumber" ordinal="1" sqlType="INTEGER"/>
</query>
<query id="employeesByIDSQL" useConfig="default">
      <sql>select * from Employees where employeesID = ?</sql>
      <result defaultNamespace="http://abc.com/empNamespace2" element="employees" rowName="employee">
         <element column="lastName" name="last-name" xsdType="string"/>
         <element column="firstName" name="first-name" xsdType="string"/>
         <element column="email" name="email" xsdType="string"/>
         <element column="phone" name="phone" xsdType="string"/>
      </result>
      <param name="employeeID" ordinal="1" sqlType="INTEGER"/>
</query>

Setting namespaces for specific elements in the query result

The row namespace applies to all elements in the query result. Alternatively, you can specify namespaces for selected elements (output mapping elements) in the query result as shown below. This namespace will only apply to that element.

This is how the setting is reflected in the WSDL.

<query id="getProductByIDSQL" useConfig="default">
      <sql>select * from Products where productID = ?</sql>
      <result defaultNamespace="http://abc.com/productIDNamespace" element="products" rowName="product">
         <element column="productID" name="productID" xsdType="string"/>
         <element column="productID" name="productID" xsdType="INTEGER"/>
         <element column="productName" name="productName" xsdType="string"/>
      </result>
</query>

Setting namespaces for complex results

In complex results in data services, the result elements can be arbitrarily nested. These nested elements can have their own namespaces. The example below shows how this is represented in a database file fragment, which has given below illustrates a query with a complex result (nested elements). As shown below, the namespace specified for the 'contact' element is inherited by the child elements that are nested within. However, if you assign specific namespaces to the child elements, the namespace inherited by the parent element will be overridden. 

<query id="customersInBostonSQL" useConfig="default">
      <sql>select  * from Customers where city = 'Boston' and country = 'USA'</sql>
      <result defaultNamespace="http://abc.com/nsb" element="customers" rowName="customer">
         <element column="customerName" name="customer-name" xsdType="string"/>
         <element namespace="http://abc.com/nsb" name="contact">
         	<element column="contactLastName" name="contact-last-name" xsdType="string"/>
         	<element column="contactFirstName" name="contact-first-name" xsdType="string"/>
         </element>
         <element column="phone" name="phone" xsdType="string"/>
         <element column="city" name="city" xsdType="string"/>
         <element column="country" name="country" xsdType="string"/>
      </result>
</query>

The WSDL created for the above service is as follows:

The resulted XML of the executed service is as follows:

Namespace inheritance in a data service

There's an inheritance order where a top-level namespace is inherited by its children. In summary, the inheritance is as follows: