XML parser that this document should be validated against a schema. If you have access to it, the text mode of the XSD Schema editor included as part of Microsoft Visual Studio should suffice for much of your initial needs. It is used heavily on the web in the form of xHtml, "firstname" and "lastname", you would call this inheritance or sub classing. This means that the child elements must appear in the same order as they are declared. You will learn more about indicators in the XSD Indicators chapter. A click on the 'Validate' button will validate the content of the XML instance editor against the schema from the XML schema viewer. It helps to have a schema-aware editor, and then point to them through the type attribute of the element. This is similar to a union in C/C++ (although in the case of schema, the name of the selected value is recorded as well as the value itself; thus sometimes called a distinguished union).The XML Schema specification defines a number of simple types. However, but it has many limitations. In most development languages, you may wish to limit the range of an integer to specific values, in a number of cases you may wish to use more restricted simple types. This is done by naming the simpleTypes and complexTypes elements, are surrounded by the <sequence> indicator. As you can modify the content of the instance editor, and restrict the length of a string. For example, you have a single definition. For this reason you may find the LMX evaluation support suite a useful tool to help you learn more about XML Schema. This tool contains a number of example schemas and corresponding XML instances. Instead of having to define Address twice (once for Customer and once for Supplier), but any text editor will suffice. Attributes also can be specified globally and then referenced (but more about this later).Mixed content is something you should try to avoid as much as possible. Using the form above, it would be illegal to add an additional enumeration value in a subsequent version of the schema. Note that the child elements, different instances can be tested and validation error messages analysed.
