Does anyone know what is DTD?

[Prashobh Mallu]

Hello friends,

I just completed HTML and started XML language. 'DTD' is one of the XML concept which seems very complicated. It is very important for me know about DTD, as it is very important concept of XML. And it is also the important part of XML schema. I wonder if you are able to let know something about the DTD. Your any help over DTD would be greatly appreciable.

[opaper]

DTD stands for "Document Type Definition". This is something that predates XML and that already existed with SGML. The DTD can define a descriptive model of structuring data in an XML document. It helps to organize data in a standardized way and allows sharing of XML documents. The DTD is not part of the XML document. It used to complete the data contained in this XML document which organized in a standardized way. That can be shared according to a common format for sharing XML documents or in a similar field of knowledge, or to meet identified needs.

[MindSpace]

Hi friend,

DTD is a separate file with an extension point DTD, which is associated with a line of programming in the XML document. That only the information in a syntax specific to the DTD. These data list the elements in the XML document, listed all syntactic rules that apply to the nesting of these elements in the XML document as a hierarchy if you want. DTD rules define the case of sequences of characters or alphanumeric sequences

[Modifier]

When you define a DTD and associate with an XML document, there are online tools that allow you to check the validity of or compliance with the XML document DTD. At this point, we say that the XML document is valid. However the DTD is not mandatory for an XML document. An XML document can not exist, then we say that it is formed. However, the DTD is highly recommended since it provides a logical organization to the XML document and from the time the XML document conforms to this logical organization.

[Praetor]

DTD existed before XML, there are some DTDs that exist in SGML. There is also a DTD, called the TEI (Text Encoding Initiative), which applies particularly in the case of exchange of text data, particularly from the fields of Humanities and literary texts. The DTD is currently used in its complete form or lean (TEI light) with XML, in fact already existed in another form with SGML. The DTD is written in a syntax of its own. There is no underlying technology for this. It is a program that operates according to precise annotations for elements, attributes, entities, etc..

[Katty]

Hi,

The DTD occurs particularly early in the design of the XML document. When digital libraries are not necessarily based on XML, it can no longer be used and what are other technologies that come into play to generate the information that should be in an XML format. XML-schema is more rigorous, perhaps more complex to develop, but offers much more than the DTD. A DTD can also define general entities. Another restriction on the ability of expression of DTD for XML over SGML is the removal of unordered groups.