CDATA is an acronym for Character DATA. CDATA section is a part of an XML document in which markup is not interpreted as markup, but is passed to the application as it is. In other words, CDATA sections are used to escape blocks of text containing characters which would otherwise be recognized as markup.
XML namespaces are used for providing uniquely named elements and attributes in an XML document. They are defined in a W3C recommendation. An XML instance may contain element or attribute names from more than one XML vocabulary.
A parser is a piece of program that takes a physical representation of some data and converts it into an in-memory form for the program as a whole to use. Parsers are used everywhere in software. An XML Parser is a parser that is designed to read XML and create a way for programs to use XML.
XPath is defined as XML path. It is a syntax or language for finding any element on the web page using XML path expression. XPath is used to find the location of any element on a webpage using HTML DOM structure.
Parsing. Parsing, syntax analysis, or syntactic analysis is the process of analyzing a string of symbols, either in natural language, computer languages or data structures, conforming to the rules of a formal grammar. The term parsing comes from Latin pars (orationis), meaning part (of speech).
The term CDATA is used about text data that should not be parsed by the XML parser. Characters like "<" and "&" are illegal in XML elements. PCDATA is text that will be parsed by a parser. Tags inside the text will be treated as markup and entities will be expanded.
A DTD defines the tags and attributes used in an XML or HTML document. Any elements defined in a DTD can be used in these documents, along with the predefined tags and attributes that are part of each markup language. The following is an example of a DTD used for defining an automobile: <!
DTD
| Acronym | Definition |
|---|
| DTD | Document Type Declaration (markup languages) |
| DTD | Dated |
| DTD | Door to Door |
| DTD | Data Type Definition (XML file validation) |
Extensible Markup Language (XML) is used to describe data. The XML standard is a flexible way to create information formats and electronically share structured data via the public Internet, as well as via corporate networks.
A document type definition (DTD) is a set of markup declarations that define a document type for a SGML-family markup language (GML, SGML, XML, HTML). A DTD defines the valid building blocks of an XML document. It defines the document structure with a list of validated elements and attributes.
XSD (XML Schema Definition) is a World Wide Web Consortium (W3C) recommendation that specifies how to formally describe the elements in an Extensible Markup Language (XML) document. XSD can also be used for generating XML documents that can be treated as programming objects.
To create a new DTD, complete the following steps:
- Create a project to contain the DTD if needed.
- In the workbench, click File > New > Other and select XML > DTD.
- Select the project or folder that will contain the DTD.
- In the File name field, type the name of the DTD, for example MyDTD.
- Click Next.
Method 1Using a Text Editor
- Find the XML file. You can use your computer's "Open With" feature to open the XML file in a text editor, which will allow you to see the XML file's code in plain-text form.
- Right-click the XML file.
- Select Open with.
- Select your computer's text editor.
- Review the XML file's code.
There are two types of external DTDs: private, and public. Rules: If any elements, attributes, or entities are used in the XML document that are referenced or defined in an external DTD, standalone="no" must be included in the XML declaration .
Disadvantages of using DTD
- It does not support the namespaces. Namespace is a mechanism by which element and attribute names can be assigned to groups.
- It supports only the text string data type.
- It is not object oriented.
- Limited possibilities to express the cardinality for elements.
Introduction to DTD
The purpose of a DTD is to define the legal building blocks of an XML document. It defines the document structure with a list of legal elements. A DTD can be declared inline in your XML document, or as an external reference.The Document Object Model (DOM) is a programming API for HTML and XML documents. It defines the logical structure of documents and the way a document is accessed and manipulated. Nevertheless, XML presents this data as documents, and the DOM may be used to manage this data.
A DTD is referred to as an internal DTD if elements are declared within the XML files. To reference it as internal DTD, standalone attribute in XML declaration must be set to yes. This means the declaration works independent of external source.
An external DTD is one that resides in a separate document. To use the external DTD, you need to link to it from your XML document by providing the URI of the DTD file. The URL can point to a local file using a relative reference, or a remote one (eg, using HTTP) using an absolute reference.
What is an XSL file? Defines the style of text, tables, and other objects within a XML document; similar to a . CSS file used by . HTML documents; can be opened with FileMaker or any program that supports XML style sheets.
Differences between an XML Schema Definition (XSD) and Document Type Definition (DTD) include: XML schemas are written in XML while DTD are derived from SGML syntax. XML schemas define datatypes for elements and attributes while DTD doesn't support datatypes. XML schemas allow support for namespaces while DTD does not.
XML Schema is commonly known as XML Schema Definition (XSD). It is used to describe and validate the structure and the content of XML data. XML schema defines the elements, attributes and data types. Schema element supports Namespaces. It is similar to a database schema that describes the data in a database.
A parser is a compiler or interpreter component that breaks data into smaller elements for easy translation into another language. A parser takes input in the form of a sequence of tokens or program instructions and usually builds a data structure in the form of a parse tree or an abstract syntax tree.
The building blocks of XML documents
- Elements. Elements are the main building blocks of both XML and HTML documents.
- Tags. Tags are used to markup elements.
- Attributes. Attributes provide extra information about elements.
- #PCDATA. #PCDATA means parsed character data.
- CDATA.
- Entities.
- Empty elements.
- Elements with data.
HTML elements are the building blocks of the HTML web page. The elements consist of a pair of tags (starting and ending tags) and the textual or graphical content inside of the tags. Inside of the tags, different attributes can be given.
Parsed Character Data (PCDATA) is a data definition that originated in Standard Generalized Markup Language (SGML), and is used also in Extensible Markup Language (XML) Document Type Definition (DTD) to designate mixed content XML elements.
Interface CDATASection
CDATA sections are used to escape blocks of text containing characters that would otherwise be regarded as markup. The only delimiter that is recognized in a CDATA section is the "]]>" string that ends the CDATA section. data attribute holds the text that is contained by the CDATA section.The basic building blocks of Javascript are the same as the building blocks of any other language - an entry point function, conditional switching (if-then, switch, etc.), loops (for, while, et al), and data structures (objects).
A valid XML document is defined in the XML specification as a well-formed XML document which also conforms to the rules of a Document Type Definition (DTD). If all tags in a document are correctly formed and follow XML guidelines, then a document is considered as well formed."
A document can only be well-formed [Section 2.1] if it obeys the syntax of XML. A document that includes sequences of markup characters that cannot be parsed or are invalid cannot be well-formed.
