Data 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.
Namespaces can be defined at different levels of a data service, which means that you can have multiple namespaces applicable to your data service at the same time. In such a scenario, the top-level namespaces will be inherited by the lower level as explained below.
See the following topics for instructions on setting namespaces at different levels of a data service:
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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 that represents the service, the namespace is indicated by the "targetNamespace" attribute. The service namespace can be set when you define a data service using the the management console as shown below.
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 data type of the Customers element falls under the given namespace as shown below.
If you have multiple queries with the same element wrapper but different element rows, be sure to use separate namespaces for each query. The example below illustrates two queries in a data service (.dbs file) with the following qualities:
Therefore, since we are using the same element wrapper for both queries, we need to use two separate namespaces to identify the two conflicting elements ('salary' and 'phone') in the two queries as shown below.
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.
If you have a data service query using the same result element multiple times, be sure to use separate namespaces for each element to avoid conflicts. The example below illustrates a single query in a data service (.dbs file) that has the same element defined twice. In this situation, we have to use separate namespaces for the two elements in order to distinguish them separately.
Setting namespaces for complex results
In complex results, the result elements can be arbitrarily nested. These nested elements can have their own namespaces. The example 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: