XSD restriction

Hi,
I'm trying to write a correct xsd using restriction.
I've the follow XML:
<root>
<a>10</a>
<b>10,54</b>
<c>2005-10-12</c>
<d>
<aa>test</aa>
<bb>test2</bb>
</d>
<d>
<cc>test3</cc>
<bb>test</bb>
</d>
</root>


I want a xsd that use restriction to: maxLeength of a element and
the cardinality ( minOccurs,maxOccurs) of the element, and some pattern
as date.

Now I can write a correct xsd?

SP