Which of the following are true about document type definition (DTD)?

A. A DTD defines the structure and attributes of an XML document.

B. With DTD, independent group of people can agree on a standard for interchanging data.

C. If DTD is declared inside XML file, it must be wrapped inside the <!DTD> definition.

D. The Library of Congress has made available a DTD to convert MARC records to XML.

E. DTD is used to ensure the authenticity of data transmitted across the web.

Choose the most appropriate answer from the options given below:

The Correct answer is A, B, and D only.

Key Points

• Document Type Definition:
  • A Document Type Definition (DTD) outlines the structure and data of a document, defining its type within the SGML family (e.g., XML, SGML, HTML, GML).
  • It consists of markup declarations that specify how a document is structured.
  • DTDs can be defined inline within an XML document or referenced externally.
  • It governs the repetition of nodes and the order of child nodes.
  • There are two data types in DTD:
    • PCDATA (Parsed Character Data): Data that is processed and parsed.
    • CDATA (Character Data): Data that is not processed or parsed.
• A DTD defines the structure and attributes of an XML document: This is true because a Document Type Definition (DTD) specifies the structure (e.g., elements, attributes) and rules for an XML document.
• With DTD, an independent group of people can agree on a standard for interchanging data: This is true because DTD helps standardize the data format for interoperability between systems.
• The Library of Congress has made available a DTD to convert MARC records to XML: This is true as the Library of Congress provides a DTD for transforming MARC (Machine-Readable Cataloging) records to XML format.

Additional Information

• If DTD is declared inside an XML file, it must be wrapped inside the <!DOCTYPE> definition is incorrect because the correct syntax for declaring a DTD inside an XML file is <!DOCTYPE> not <!DTD>.
• DTD is used to ensure the authenticity of data transmitted across the web is incorrect because DTD is about defining structure and not ensuring the authenticity of data (for authentication, you would use other technologies like XML Signature).