What are SQL and servlets?

Structured Query Language (Structured Query Language), referred to as SQL (pronounced: /ˈes kjuː ˈel/ "S-Q-L"), is a special-purpose programming language and a database query and programming language. Language used to access data and query, update and manage relational database systems; it is also the extension of database script files.

In JSP, Servlet is another important technology. Its full name is Java Servlet. It is mainly used for server-side programs written in Java classes and has nothing to do with platform architecture and protocols. . In JSP, all JSP pages must be converted into Servlets for compilation and execution when sent back to the server.

Definition of Servlet

Servlet is a Java technology that focuses on CGI development. It runs on the server side and produces dynamic results. Why use Servlet instead of traditional CGI program?\

One of the reasons is efficiency. Using traditional CGI program, every time an HTTP request is received, the system will start a new process. Processing this request will result in reduced system performance. With Servlet, Java VMS is always running. When receiving a request, Java MVS creates a Java thread to process it immediately, which is much more efficient than starting a new system process every time.

JSP is an extension of Seivlet technology. JSP allows Java code to be easily mixed with HTML language and complete powerful functions. It makes it easier to read the code and view the results of the program execution in the browser.

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