CSC 4710 Lecture Notes - Lecture 21: Xml, Empty Set, Xquery
16 Dec 2019
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Document Summary
Import is used to share schemas developed by different groups at different sites. Included schemas are usually under the control of the same development group as the including schema. Included and including schemas must have the same target namespace (because the text is physically included) schemalocation attribute required. Schemas are under the control of different groups. The import statement must tell the importing schema what that target namespace is schemalocation attribute optional. Extension and restriction of base types: mechanism for modifying the types in imported schemas. Extending an xml schema type means adding elements or adding attributes to existing elements: restricting types means tightening the types of the existing elements and attributes (i. e. , replacing existing types with subtypes) So far all types were named: useful when the same type is used in more than one place, when a type definition is used exactly once, anonymous types can save space.
