Most recent edit on 2005-12-07 16:10:39 by Admin
Additions:
Deletions:
XML (Extensible Markup Language) is a W3C Recommendation for creating special-purpose markup languages. It is a simplified subset of SGML, capable of describing many different kinds of data. Its primary purpose is to facilitate the sharing of structured text and information across the Internet. Languages based on XML (for example, RDF, SMIL, MathML, XSIL and SVG) are themselves described in a formal way, allowing programs to modify and validate documents in these languages without prior knowledge of their form.
XML vocabulary
A set of related XML elements. Generally the elements within a vocabulary are associated with a common business context (such as a business task or a logical business model).
XML schema
A data model that defines the structure, validation constraints, and relationships of the elements within an XML vocabulary.
XSD schema
An XML schema implemented using the XML Schema Definition (XSD) Language.
XML document
A data set organized and described by XML meta tags. An XML document can optionally be associated with an XML schema that formally defines its structure and data rules.
The fundamental characteristics that differentiate XML documents and XML schemas are:
- an XML document contains data, an XML schema does not (except for data used to validate the XML document)
- an XML schema defines the structure of an XML document and is capable of supplementing that structure with rules and constraints
- an XML document contains structure that can be derived from an associated XML schema
- the structure within an XML document is dictated by the XML Language specification; a document that conforms to this specification is considered a "well-formed XML document"
- when an XML document is associated with an XML schema and when that document contains data that does not violate any of the schema's rules, the XML document is considered a "valid XML document"
- a valid XML document is often referred to as "an instance" of its associated schema and/or its associated vocabulary
Using a relational database as a comparison, its physical data model (or a subset thereof) is the equivalent to an XML schema. A record of data retrieved from a database is comparable to an XML document instance. The main difference with XML documents is that they are always supplemented with meta information and a hierarchical structure.
Here are some other considerations:
- a single XML schema can represent a subset of a vocabulary, an entire vocabulary, or multiple vocabularies
- a single XML schema can be implemented using one or more schema languages
- it is common for product documentation to refer to "XSD schemas" as "XML schemas" (this can be acceptable when the use of XSD is standardized and therefore implied with any reference to XML schemas)
- the term "element" is generally used when designing XML schemas or XML document structures, whereas the term "meta tag" is commonly used to refer to elements in their implemented state (within XML documents)
Read further on Wikipedia∞.
Oldest known version of this page was edited on 2004-04-01 14:53:41 by Roland Stens []
Page view:
Extensible Markup Language
XML (Extensible Markup Language) is a W3C Recommendation for creating special-purpose markup languages. It is a simplified subset of SGML, capable of describing many different kinds of data. Its primary purpose is to facilitate the sharing of structured text and information across the Internet. Languages based on XML (for example, RDF, SMIL, MathML, XSIL and SVG) are themselves described in a formal way, allowing programs to modify and validate documents in these languages without prior knowledge of their form.
XML vocabulary
A set of related XML elements. Generally the elements within a vocabulary are associated with a common business context (such as a business task or a logical business model).
XML schema
A data model that defines the structure, validation constraints, and relationships of the elements within an XML vocabulary.
XSD schema
An XML schema implemented using the XML Schema Definition (XSD) Language.
XML document
A data set organized and described by XML meta tags. An XML document can optionally be associated with an XML schema that formally defines its structure and data rules.
The fundamental characteristics that differentiate XML documents and XML schemas are:
- an XML document contains data, an XML schema does not (except for data used to validate the XML document)
- an XML schema defines the structure of an XML document and is capable of supplementing that structure with rules and constraints
- an XML document contains structure that can be derived from an associated XML schema
- the structure within an XML document is dictated by the XML Language specification; a document that conforms to this specification is considered a "well-formed XML document"
- when an XML document is associated with an XML schema and when that document contains data that does not violate any of the schema's rules, the XML document is considered a "valid XML document"
- a valid XML document is often referred to as "an instance" of its associated schema and/or its associated vocabulary
Using a relational database as a comparison, its physical data model (or a subset thereof) is the equivalent to an XML schema. A record of data retrieved from a database is comparable to an XML document instance. The main difference with XML documents is that they are always supplemented with meta information and a hierarchical structure.
Here are some other considerations:
- a single XML schema can represent a subset of a vocabulary, an entire vocabulary, or multiple vocabularies
- a single XML schema can be implemented using one or more schema languages
- it is common for product documentation to refer to "XSD schemas" as "XML schemas" (this can be acceptable when the use of XSD is standardized and therefore implied with any reference to XML schemas)
- the term "element" is generally used when designing XML schemas or XML document structures, whereas the term "meta tag" is commonly used to refer to elements in their implemented state (within XML documents)
Read further on
Wikipedia∞.