All operations of the GME work with the Class Model shown below, which is a representational model for describing XML Schemas and their dependencies.

The primary means by which an XML Schema is identified by external entities is its targetNamespace (see the XML Schema Specification). This is a URI, and is represented as such in the GME model when used as an attribute within a class (such as in the XMLSchema class), but is represented using the XMLSchemaNamespace when used by itself (such as when it is the input or output of an operation).

XML Schemas can be comprised of multiple actual "documents." As such, the GME model represents XML Schemas using the XMLSchema class, which consists of one or more XMLSchemaDocuments. An XMLSchema has a targetNamespace a "root" document (XMLSchemaDocument), and zero or more additional documents (XMLSchemaDocuments). Each XMLSchemaDocument has a unique (within an XMLSchema) identifier, represented by the systemID attribute (see the XML Specification), and the actual text of the document, represented by the schemaText attribute.

The XMLSchema, XMLSchemaDocument, and XMLSchemaNamespace are the only Classes the GME client uses to describe XML Schemas to the GME service. The GME service uses two additional Classes, XMLSchemaBundle and XMLSchemaImportInformation to describe, to the client, additional details about how XML Schemas relate to each other. The XMLSchemaImportInformation Class is used to describe the set of XML Schemas (identified via a set of XMLSchemaNamespace representing their targetNamespaces) imported by a given XML Schema (identified via its targetNamespace). The XMLSchemaBundle class conceptually represents a graph of XML Schemas. It is a complex data structure which contains a set of XMLSchema and a set of XMLSchemaImportInformation and utility methods to interrogate those sets, such as getImportedSchemasForTargetNamespace{*}.