A complex element is an XML element that contain other elements and/or attributes.

There are four kinds of complex elements as follows:

• empty elements
• elements that contain only text
• elements that contain only other elements
• elements that contain both other elements and text

Note: Each of these elements may contain attribute as well!

A complex XML element, "product" which is empty:

A complex XML element, "employee", which contains other elements:

A complex XML element, "food", which contains only the text:

A complex XML element, "description", which contains both text and elements:

Look at this complex XML element, "employee", which contain only other elements:

We can define a complex element in an XML Schemas two different ways:

1. The "employee" element can be declared directly by naming the elements, like this:

If you use the method described above, only the "employee" element can use the specified complex types. Note that the child element, "firstname" and "lastname", are surrounded by the <sequence> indicator. This mean that the child elements must appear in the same order as they are declared. You will learn more about indicator in the XSD Indicators chapter.

2. The "employee" element can have a type attribute that refer to the name of the complex type to use:

If you use the method described above, several elements can refer to the same complex types, like this:

You can also base a complex element on existing complex element and add some elements, like this: