What is RDF?

 

RDF is the abbreviation of Resource description framework, that is, the Resource Description Framework.

RDF is an XML application that processes metadata. The so-called metadata is "data describing data" or "information describing information ". It may be difficult to understand the metadata. For example, the content of a book is the data of a book, and the author's name, publisher's address, or copyright information is the metadata of the book. The division of data and metadata is not absolute. Some data can be processed as either data or metadata. For example, the author's name can be processed as data rather than metadata.

As we all know, the description of resources is related to fields and applications. For example, the description of a book is different from that of a web site, that is, the description of different resources should adopt different vocabulary. Therefore, the RDF specification does not define the vocabulary used to describe resources, but defines some rules which must be followed when defining the vocabulary used to describe resources in various fields and applications. Of course, RDF also provides a basic vocabulary for describing resources.

With RDF, people can use their own vocabulary to describe any resource, but people prefer to use it to describe web sites and pages. Because structured XML data is used, the search engine can understand the precise meaning of metadata, making the search more intelligent and accurate, completely avoiding the current situation where the search engine often returns irrelevant data. Of course, the premise is that the RDF and standardized RDF vocabulary are widely used on the web, and the search engine needs to be able to understand the vocabulary used.

Simply put, an RDF file contains multiple resource descriptions, and a resource description is composed of multiple statements. A statement is a Trielement consisting of resources, attribute types, and attribute values, indicates an attribute of a resource. The statements in the Resource description can correspond to the statements in the natural language. The resource corresponds to the subject in the natural language. The attribute type corresponds to the predicate, and the attribute value corresponds to the object. Since natural language statements can be passive sentences, the preceding simple correspondence is just a conceptual analogy.

Resource Description Framework (RDF) is a language used to express information about resources on the World Wide Web. it is used to express metadata about web resources, such as the title, author, and modification time of web pages, copyright and license information of Web documents, and an available schedule of shared resources. However, after the concept of "Web resource" is generalized, RDF can be used to express information about anyIdentifierEven if sometimes they cannot be directly obtained from the WebObtain. For example, information about a product of an online shopping organization (for example, information about specifications, prices, and availability), or descriptions about a Web user's preference in information delivery.

Reprinted from http://blog.csdn.net/everybody2005/archive/2004/10/20/145038.aspx