An xml vocabulary should be designed in such a way that the applications that process it do not break when it is inevitably changed. Extending and versioning xml languages part 1 described extending and versioning xml with little focus on the schema language used. Im also considering a json version for this as an alternative and for the future organizations that would need integration between their system to our system. The incremental schema will then contain only the updated definition and will use a new versioned namespace. The inevitable evolution of these languages is called versioning. Xsd practice is to give the schema a new identity namespace if any. What is the best practice for versioning xml schemas. This document describes use cases where xml schemas are being versioned. This paper will outline an approach using an extension to namespace using directives, and a careful arrangement of nested namespaces within namespace std. It does not explain the technical details of any earlier releases. Published in 2003, the xml design rules and conventions v1.
It is of similar importance to software writers to know exactly the version of. Alternately, open the file as code, rightclick in the editor, and select show xml schema explorer. Minor versions are interim releases of an xml schema that contain only the. In particular, on the behaviour of xml schema processors, which performs schema validation and exposes information via the post schema validation infoset psvi. Oxygen xml editor is the premier text editor for xml geeks, and an indispensable tool for oreillys production group. These configuration elements are introduced using a namespace for each module and associating the namespace with the schema. Typically, the uri chosen for the namespace of a given xml vocabulary describes a resource under the control of the author or organization defining the vocabulary, such as a url for the authors web server. This tutorial explains the use of namespaces with xml schema xsd. Schema versioning is also important to other types of systems, such as for the. It is clear that xml schemas will evolve over time or they could contain bugs to be fixed, so it is important to capture the schema s version and to have some mechanism to bind against a specific version. It is placed in a namespace to ensure that it does not collide with any of the elements other attributes. Suppose that a new version of a xml schema is created using the same namespace, as described above. Cisco ios xr xml api guide, cisco ios xr release 4.
Xml design rules and conventions drc for the exchange. Xml schema versioning namespace world wide web consortium w3c. Xml is designed for the creation of languages based upon selfdescribing markup. Editorial draft extending and versioning xml languages. Software specification artifacts versioning for swim. The delta schema may leverage xml schema inheritance and imports from the original version, or previous deltas to reduce the. And the version information is available from dom, sax, xslt, or any other normal xml processing technology. Xml namespaces are an integral aspect of most of the w3cs xml recommendations and working drafts, including xpath, xml schema, xslt, xquery, soap, rdf, dom, and xhtml. The choices, decisions, and strategies described in part 1 are augmented with schema instances herein. Xschema 6,7,8 is a framework a language and a suite of tools for the creation and validation of timevarying xml documents.
Provide xml andor json schemas for all usereditable files. Creating a custom xml namespace mulesoft documentation. An update to this article has been posted here on 102704. The resource can be an xml document, a dtd, a stylesheet, a schema, or even non xml data associated with an xml resource, the canonical url is the url where the master copy of that resource is expected to be present on the web. A couple of simple principles help you to keep your xml formats flexible. A significant downside with using version identifiers is that software that supports both versions of the name must perform special processing on top of xml and namespaces. Using meaningful namespace prefixes add clarity to the xml document. This declaration tells the schemavalidator that all the elements used in this xml document are declared in the s. The mtconnect standard takes advantage of the latest advances in extensibility to add additional properties in a regulated manor using the xs. A namespace name is a uniform resource identifier uri.
The major version number of the schema is specified in the schema namespace. Understanding namespaces lenz consulting group, inc. Xml report definition telerik reporting documentation. Suppose a corporations headquarters had a corporatewide namespace. Note that when referencing a version, the patch number is assumed to be zero if it is omitted. Part 2 focus on the schema language specific aspects of extending and versioning xml. The network devised a comprehensive component versioning strategy, the xml namespace conventions were. W3c xml schema, and xml namespaces in language construction and extension. Good schema management helps to maintain xml namespace. To make the version information a more immediate property of the xml information items, you can place them in xml namespaces that reflect the version. It is of similar importance to software writers to know exactly the version of the schema that they are using. Either way you get a view like the one below when mostly expanded.
Once you have the xml schema instance namespace available. The toplevel version attribute works whether i use an xml schema system or not. The current release is an architecture upgrade from the previous version. Mar 18, 2003 good schema management helps to maintain xml namespace. Xml validation, using dtd, xml schema, relax ng, or schematron. If you choose not to use an xml data binding tool, you may be advised to refer to the xsd standard and invest in a good book regarding xml schema. You can use several techniques for versioning xml schemas, such as defining special root attributes or using the dtd. It is a convention to use xsd or xs as a prefix for the xml schema namespace, but that decision is purely personal. The core of this issue is the notion of canonical url of an xml resource. Visit our site to download the scorm manifest xml schema definition files for scorm 1.
To avoid breaking namespace aware applications with each new version of an xml schema use the same namespace for all versions. However, the spec says explicitly that the infoset used as a schema document does not necessarily come directly from parsing an xml document but may be a synthetic infoset, the output of some other process. A schema document may include other schema documents for the same namespace, and may import schema documents for a different namespace. Do put a version attribute in the xml instance document. For example, many components bind xml types into particular programming language types. Even if there is only one program involved, you may be faced with the issue of xml versioning as you build new releases of the program. Software specification artifacts versioning for swim enabled. We are also using schema versioning from xml schema 1. If you are creating and modifying xml documents validating against xml schema making use of namespaces, then xml data binding will save you a great deal of time as mostly removes this complexity. The anyattribute element enables the author to extend the xml document with attributes not specified by the schema.
Once you release software or a specification for version 1. Jul 21, 2004 designing extensible, versionable xml formats. Xml design rules and conventions drc for the exchange network. This can also lead to some awkwardness in code that dispatches according to version. Hence, versioning mechanisms in xml schema should new versions to be created, and the schema processors need to handle instances defined by the different versions. Creating a custom xml namespace xml schema definitions are used for each module to define the objects and properties that the module makes available to mule runtime. A tool could then be used to obtain the correct version of the. The text assumes that you have a basic understanding of xml, namespaces in xml, and xml schema. Obasanjo recommends introducing new namespaces for your xml format extensions. The bug is found within the schema and all schema instances must comply with the fixed version. I dont even want to use xml if it was not because our users use xml rather than json.
What are the best practices for versioning xml schemas. Guide to versioning xml languages using new xml schema 1. This document describes the xml schema versioning namespace and provides links to related resources, using resource directory description language. Xml schema versioning best practices 1 capture the schema version somewhere in the xml schema. So applications will need to cope with different versions coexisting in the system. The namespace declarations are intentionally overcomplicated to illustrate their scope. Xml schema is to define the legal building blocks of an xml document, gs1 schema design allows developers to supply information embedded within xml documentation. There are many possible mappings of xml schema constructs to namespaces and to. This is a more complex example of an instance with elements in multiple namespaces. Xml schema versioning use cases world wide web consortium. Xml namespaces and how they affect xpath and xslt slashdot. The version attribute approach is taken by the xslt language itself. One can choose to use a prefix abc for the xml schema namespace, which is legal, but doesnt make much sense.
This document describes the desirable behaviours for use cases that involve xml schema versioning. Editorial draft extending and versioning xml languages part. Place the new version of a schema at a new location to avoid breaking old instance documents. For a clear visual representation of the schema, open the schema file in visual studio in design mode and click on the xml schema explorer link. It is clear that xml schemas will evolve over time or they could contain bugs to be fixed, so it is important to capture the schemas version and to have some mechanism to bind against a specific version. Versioning of xml schema and namespaces from eliot. A related problem occurs because, to namespaceaware xml parsers, the element. Schema versioning is also important to other types of systems, such as for the application and for code generators using xml schemas. Gs1 xml standards are an organized suite of xml schema modules. My team uses oxygen xml editor for everything from simple xml editing to schema validation and xslt transformations.
Xml data binding tool, you may be advised to refer to the xsd standard and invest in a. As of august 2015, the lowest supported version is 863 this topic describes ebays versioning strategy for the trading api and shopping api, which enables us to evolve the schema while maintaining backward compatibility for at least 18 months. Every time you change the namespace, you will break all processing applications. Versioning of xml schema and namespaces from eliot kimber.
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