XML Schema (XSD) facts: which statement is NOT true about XML Schemas?

Introduction / Context:
XML Schema (XSD) is the modern, expressive way to validate XML documents. Knowing what XSD is (and is not) helps you design robust data interchange contracts. This question asks for the statement that is not correct.

Given Data / Assumptions:

• XSD describes element/attribute structure, simple and complex types, and constraints.
• XSD files are written in XML and use a specific namespace (e.g., http://www.w3.org/2001/XMLSchema ).
• Conceptually, XSD defines a vocabulary (symbols) and their relationships.

Concept / Approach:
The incorrect statement is that XML Schemas “have their own syntax.” XSD documents use standard XML syntax (tags, attributes, nesting). They do not introduce a non-XML syntax; instead, they define schema-specific elements/attributes within XML.

Step-by-Step Solution:

Verification / Alternative check:
Opening any .xsd file reveals an XML document with xsd:element, xsd:complexType, etc., proving the shared XML syntax.

Why Other Options Are Wrong (they are true):

• (a) and (b): XSD defines permissible content and relationships.
• (c): XSD documents are XML documents.

Common Pitfalls:
Confusing “schema vocabulary” with “syntax.” XSD does define its own elements and attributes, but still within standard XML syntax.

Final Answer:
They have their own syntax.