Like THML, XML is also derived from SGML (an old-fashioned general-purpose markup language of Standard General Mardup â€‹â€‹Language), which retains 80% of SGML functionality and reduces complexity by 20%. However, XML has a lack of HTML language. Great scalability and flexibility. XML no longer has the same format as HTML. XML is actually a definition language, that is, users can define endless tags to describe any data element in the file, thus breaking the constraints of the HTML fixed tag set, making the file content richer and more complex and forming a complete Information system.
The XML language allows the information provider to define the tag and attribute name as required, as well as the description method, so that the structure of the XML file can be complex to any degree. There are three main elements of XML: Schema (Schema), XSL (eXtensible Link Language). Schema specifies the logical structure of the XML file, defines the elements in the XML file, the attributes of the elements, and the relationship between the elements and the attributes of the elements. It helps the XML parser to check the legitimacy of XML markups; XSL is used to A language that specifies the style of an XML document. It enables the Web browser to change the representation of the document on the client side so that it does not need to communicate with the server anymore; XLL will further extend the existing simple links on the Web. Good data storage format, extensibility, high degree of structuring, and ease of network transmission are the four main features of XML. Since XML can define its own markup language for specific applications, this feature makes XML available in e-commerce, government documents, reporting, judicial, publishing, federation, CAD/CAM, insurance agencies, vendors, and intermediary organization information exchange. To show their talents, according to different systems, vendors provide unique solutions.
The application of XML can be divided into four categories:
1. Can interact with different data sources based on customer needs. In this kind of application, XML solves the problem of unified interface of data. However, unlike other data transfer standards, XML does not define specific specifications for the appearance of data in data files. Instead, it adds tag passing and logical structures and meanings to the data. This makes XML a specification that the program can automatically understand.
2. A large amount of computing load can be distributed on the client, that is, the client can select and make different applications to process data according to his own needs, and the server only needs to issue the same XML file. XML gives the customer the initiative to process data, and the server only makes the data as complete and accurate as possible encapsulated into an XML file. The self-explanation of XML enables the client to understand the logical structure of the data while receiving the data, thus enabling a wide range of general-purpose distributed computing.
3. The same data can be presented to different users with different features.
4. The network agent can edit, increase or decrease the information obtained to suit the needs of individual users. Some customers obtain data not for direct use but for organizing their own databases as needed. For example, the Ministry of Education establishes a large bank of questions. When the exam is taken, the questions in the bank of questions are taken out to form test papers. The papers are then packaged into XML files. Each school allows them to pass a filter, filter out all the answers, and send them to each. In front of the candidates, unfiltered content can be sent directly to the teacher. Of course, an answer compilation can be sent after the test. In addition, the XML file can also include other relevant information such as degree of difficulty, previous error rate, etc., so that only a few small programs can be used to transfer the same XML file into multiple files to different users.
Based on the above four different types of applications, we can conclude that XML actually originated from a philosophy of â€œdata is owned by the user and the user is happyâ€. Specifically, data producers do not consider the specific uses of these data in the future. They only consider the information that may be used in the future as much as possible, and make it complete and standardized into XML files. Service providers do not Will be detained in the cage of a specific scripting language, production tool, and transmission engine, but will provide a standardized, independently marketable, level-approved field where different production and transmission tools will be visually appealing and decisive. Male and female, thereby greatly satisfying the needs of customers and becoming a trustworthy service provider.
A vacuum flask (also known as a Dewar flask, Dewar bottle or thermos) is an insulating storage vessel that greatly lengthens the time over which its contents remain hotter or cooler than the flask's surroundings. Invented by Sir James Dewar in 1892, the vacuum flask consists of two flasks, placed one within the other and joined at the neck. The gap between the two flasks is partially evacuated of air, creating a near-vacuum which significantly reduces heat transfer by conduction or convection.
Vacuum flasks are used domestically to keep beverages hot or cold for extended periods of time and for many purposes in industry.
Stainless Steel Vacuum Bottle,Thermos Flask Bottle,High-Capacity Vacuum Bottle
HOMEARTS INDUSTRIAL CO.,LTD , http://www.homeartschina.com