- Industry compatibility: Any internal schema should be seen as a possible candidate for external Web services interchange once the intra-enterprise infrastructure has been established. For this reason, it is worth looking at the existing literature to see what the de facto standard is for that industry group. The advantage to this comes from the fact that the closer a company standard is to an existing global standard, the easier it will be to write code that will transform one to the other for B2B compatibility.
- Modularisation: It is far better to create a schema from existing schema parts than it is to try to create entire schemas from scratch. Not only does this make it easier to maintain such schemas, but the schemas can also drive the modelling of programming class hierarchies, reducing the amount of custom code needed to manipulate the XML within applications.
- Versioning: As a company evolves, so too do the requirements it places upon its schemas and other software. A schema manager is responsible for ensuring that different versions of a given schema don't create forks in a company's applications, a concern that's especially high in a distributed Web services environment.
- Ease of validation: The buzzword acronym in XML circles right now is PSVI (post-schema-validation infosets). An infoset is an abstract representation of the XML contents, independent of the syntactical markup symbols. As an XML parser validates the XML data against its associated schema to ensure that all of the data is valid and the structure is sound, it can also convert the data internally to the datatypes specified in the schema. In essence, the resulting infoset has become a distinct binary object and can be manipulated in that fashion. Providing an efficient mechanism for ensuring that such schemas are readily accessible and consistent is another role that a schema manager will likely play, especially as PSVI data from Web services become the norm.
- Be familiar with Web services architectures in varying flavors (.Net, Java, and a whole host of others within the open source realm), SOAP, and WSDL.
- Know about traditional databases to understand how the schema specifications within existing data stores can affect the XML schemas that will likely represent this data in transition.
- Know such languages as XPath and XSLT.
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