Detailed description of Web Service description language WSDL (1) -- Why does it use WSDL? [Convert]-Web_Serv

Are standards such as Internet protocols used by authority, or are people looking at them as the benefits far exceed the cost? Many standards have been aborted. Sometimes, the standards that are not yet widely used are even forcibly introduced by laws or government regulations: the Ada language is an example.
I believe that it is the benefit of following standards that makes it widely accepted. For example, what is really important for railway services is that the railways laid by different companies are combined, or the products of several companies are coordinated. Several large enterprises have jointly established the SOAP standard. The Web Service Description Language (WSDL) has introduced a convenient way to coordinate the work to Web Service providers and users, so that we can more easily obtain the benefits of SOAP. It is not difficult for several companies to get their railways together. They only need to follow the standard distance between the two tracks. For Web services, this is much more complicated. We must first specify the standard format for the specified interface.
Some people once said that SOAP does not really need any interface description language. If SOAP is a standard for communicating pure content, a language is required to describe the content. SOAP messages do contain certain types of information, so SOAP allows dynamic determination of types. But I do not know the function name, number of parameters, and their respective types of a function. How can I call this function? Without WSDL, I can determine the call syntax from the required documents or check the message. Anyone must participate in any method. This process may be wrong. With WSDL, I can use this cross-platform and cross-language method to automate the generation of Web Service proxies. Just like the IDL files of COM and CORBA, the WSDL files are agreed by the customer and the server.
Note that since the WSDL is designed to bind protocols other than SOAP, we mainly focus on the relationship between WSDL and SOAP over HTTP. Similarly, since SOAP is currently mainly used to call remote processes and functions, WSDL supports the documentation specification for SOAP transmission. WSDL 1.1 has been submitted to W3C as a record (see http://www.w3.org/TR/wsdl.html)
WSDL document structure
To understand the XML document, it is very useful to think of it as a block chart. The following figure illustrates the structure of the WSDL in XML format. It reveals the relationship between the five columns of the WSDL document.
The WSDL document can be divided into two parts. The top part consists of abstract definitions, and the bottom part consists of specific descriptions. Abstract parts define SOAP messages in a way independent of platform and language. They do not contain any random generator or language-changing elements. This defines a series of services that can be implemented by different websites. Something that varies with the website is classified as a bottom score, because it contains a specific definition.