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Definition

In XML, you can assign element names and attribute names to a namespace in order to differentiate them from other elements and attributes with the same name, which come from other XML documents. Namespaces are identified in XML documents by a URI (Unified Resource Identifier) and are used in the XML document by means of a prefix.

Tip

The attribute xmlns:xsd="http://www.w3.org/2001/XMLSchema" identifies the default namespace for XML schema in an XML document. The attribute xmlns assigns the prefix xsd to the URI http://www.w3.org/2001/XMLSchema. This prefix can also serve as a qualifier for tags in the document.

Use

Namespaces in the Enterprise Services Builder

  • Repository namespaces are displayed in the ES Builder (Design) navigation tree. They are all assigned to a software component version but are used differently:
    • Repository namespaces are used to avoid naming conflicts. It is not possible to have duplicate object names in an object type within a repository namespace. In other words, a repository namespace is a quantity in the ES Repository in which the object names are unique.
    • Software component versions are used to define shipment units. It is not possible to ship design objects in a namespace (integration scenario objects, integration process objects, interface objects, mapping objects, and adapter objects) on their own. Instead, they are shipped as a part of the relevant software component version.

    Although repository namespaces are assigned to the software component version in the navigation tree, the software component version does not affect the uniqueness of the object names.

  • XML namespaces are used as identifiers for message instances or customer-specific fields in the instance. You can specify XML namespaces as an attribute of (fault) message types and data type enhancements.
    Note

    The length of namespaces in the ES Builder is restricted to 255 characters.

Other Namespaces

  • Namespaces in the System Landscape Directory (SLD), which have nothing to do with repository or XML namespaces (see: Name Reservation ).
  • Internal namespaces, which are required in message instances, for example. The internal namespace for fields in the message header is: http://sap.com/exchange/MessageFormat, for example. These namespaces are of no further interest for SAP NetWeaver users.
Structure

Basically, a namespace in XML can be any constant value. Note the following two conventions:

Usual Conventions for Repository and XML Namespaces

Prefix Use

http://

When you specify an HTTP address as a namespace this does not mean that you can access additional information about the namespace from this address (in some cases an XML schema definition is hidden behind the address). The HTTP address used merely ensures that the name of the namespace is unique. SAP namespaces adhere to the standard http://sap.com/xi/<Name>.

urn:

Namespaces with this prefix have no value in the sense that they are not connected with a Web page in the Internet.

It is assumed that conventions ensure that namespaces are unique.

Note

For further information about namespaces, see www.w3.org/TR/REC-xml-names/.