The DTD follow SGML syntax but the
Schema document is an XML document.
In DTD everything is treated as text
where as the Schema supports variety of dataTypes similar to programming
language.
In Schema, we can inherit, create
relationship among elements but not possible in DTD.
What Is DTD?
The DTD stands for Document Type
Definition and used to define the legal building blocks of an XML document.
DTD defines rules for a specific type of
document i.e.
1. Names of elements
2. Order of elements
3. Proper nesting and containment of elements
4. Element attributes
What Is XML Schema Element?
The schema element defines the root
element of a schema.
As an Example,
<?xml version="1.0"?>
<xs:schema
xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:element name="values"
type="xs:string" />
</xs:schema>
How To apply a DTD to an XML
document?
Include the DTD's element definitions
within the XML document itself. Also provide the DTD as a separate file, whose
name you reference in the XML document.