Designing Your own XML Schema: Constraining with Restrictions

In this section, we shall go through an example covering most of the important data types available in the XML Schema definition.  Let us have a look at the following XML schema now:

According to the above example, the document root element would be “Employees.”  The element “Employees” internally can contain “Employee” elements.  The element “Employee” internally contains a few more elements: “Name,” “Hiredate,” “isMarried,” “Salary” and “Age.”  You should observe that there could be any number of “Employee” elements within “Employee.” 

You should also observe that “Name,” “HireDate,” “isMarried,” “Salary” and “Age” are defined with different simple data types rather than with “complex types.”  The only complex elements are “Employees” and “Employee.”  I also declared an attribute ID for the “Employee” element as follows:

Another important point to observe is that the “isMarried” element is declared as optional.  This is possible by making “minOccurs” be “0” (default is “1”).

Now, how would the XML document look when it conformed to the above XML Schema?  The following would be a sample XML document which conforms to the XML Schema above.