Solution | Problem 17, question: What is the difference between using the AddNew method of ADO in ASP and using the "Insert into ..." statement directly? Which Way is better?
A: The AddNew method of ADO only encapsulates "Insert into" statement, so when manipulating large amounts of data, using SQL statements directly will greatly speed up access to data because it reduces the "translation" Time of ADO. Because the operations performed by SQL statements are performed directly on the database server, they have a significant advantage, especially when the data volume is large.
18. Question: Why do I use standard Insert record statements in ASP to insert into books (Name,email) VALUES ("Kitty", "kitty@263.com") will be wrong?
A: SQL (structured Query language/Structured Query language) is a data query language developed by IBM in the 1970 's and is now the standard for relational database query languages. An SQL statement is an English based program language that you can use to add, manage, and Access databases.
Strings that are added in an SQL statement can use double quotes, but in an ASP you need to use single quotes for normal execution. It should be written as insert into books (Name,email) VALUES (' Kitty ', ' kitty@263.com ').
19. Question: What is an ActiveX control? Where can I get these ActiveX controls?
A: Microsoft ActiveX controls are reusable software components developed by software vendors. In addition to the ASP's embedded objects, additional installed ActiveX controls can be used in ASP, which can save a lot of valuable development time, in fact, in the ASP also embedded a lot of ActiveX controls can be used.
With ActiveX controls, you can quickly add special features to Web applications and development tools. For example, use the AdRotator object to make the advertisement scroll board, use the FileSystemObject object for file access, and use the marquee object to implement scrolling text.
There are now more than 1000 commercially available ActiveX controls that can be developed using a variety of programming languages such as c,c++, as well as Microsoft Visual Java Development Environment, Microsoft visible J + +. Once the ActiveX control has been developed, the design and developers can use it as a preinstalled component for developing client programs. Using ActiveX controls in this way eliminates the need for consumers to know how these components are developed and, in many cases, do not even have to program themselves to complete the design of a Web page or application.
There are more than 1000 commercial controls currently provided by third party software developers. The Microsoft ActiveX component Library (ActiveX Component Gallery) has information and associated connections that point to a variety of ActiveX controls provided by Microsoft and third party developers. In the Microsoft ActiveX component Library (ActiveX Component Gallery), you can find a list of companies that develop Internet-enhanced ActiveX controls.
20, Question: Why Use strstartport= (Request.Form ("catmenu_0") statement to take the value of the starting site in the form is not found in the database?
A: This is because the value of the starting site you are taking may have spaces, for example, the original intention is "Hangzhou", but because the space exists, the ASP program to take the value may be "Hangzhou", and the database only "Hangzhou" record, of course, can not find, the solution is to use the TRIM function will be the two spaces of the string to remove all, The corresponding statement is:
Strstartport=trim (Request.Form ("Catmenu_0"))
21, the problem: in the ASP when the life cycle of the variable, there are several ways to retain variable content?
A: Any action that causes the end of a Web page, such as pressing the "Refresh" button on the browser, or closing the browser, and then reopening it, will result in the end of the variable life cycle.
If you want to keep the contents of a variable at the end of a Web page for the next execution, you can use the Application object to implement it. For example, you can use the Application object to make statistics web site traffic counters.
The session object, like the Application object, stores the contents of the variable at the end of the Web page, but unlike the Application object, each online is a separate sessions object. Simply put, all online Internet users share only one application object, but each online surfer has its own session object.
The Application object and the session object can help us record the information on the server side, while the cookie object will record the information on the client with the help of the cookies provided by the browser. It is important to note that cookies are recorded in the browser information, so the data access is not as easy as accessing other ASP objects (information stored on the server side) so simple, in practice, only when the browser started browsing a server's Web page, The browser is able to exchange cookies data with the server before the server has downloaded any data to the browser.
22. Question: What should be done after the object is used?
A: When you finish using the object, you first use the Close method to release the system resources occupied by the object, and then set the object value of "Nothing" to free up the memory occupied by the object, otherwise the Web Service site will run inefficient or even crash because of too many objects, as follows:
<%
Object. Close
Set object = Nothing
% >
23. Question: Are there several ways to read HTML form fields in an ASP file?
A: The Request object can read the contents of an HTML form field in addition to the parameters that are attached to the URL behind it, and the syntax structure that is often used is as follows:
< Form name =formname method= "get| Post "action=" URL >< Form >
The method can accept methods of getting or post two transmissions, where the post is a method that allows large amounts of data to be transmitted, and the Get method will attach the data to be transferred behind the URL and then serve the server together, thus limiting the amount of data transferred. But the execution efficiency is better than the Post method.
You can use the Get or POST method to send data to the server, and the corresponding method for receiving data using the Request object is as follows:
Get:Request.QueryString ("field name") can also be written as Request ("Field name")
Post:Request.Form ("field name") can also be written as Request ("Field name")
24, question: How to improve the efficiency of using the request collection?
A: When using the Request collection, it is much slower than accessing a local variable because it contains a series of searches for the related collection. Therefore, if you intend to use a value in the request collection more than once in a page, you should consider storing it as a local variable.
25. Question: Can you use VBScript in ASP pages, or use JScript to mix script engines?
A: Although you can use VBScript in ASP pages, you can also use JScript. However, it is not advisable to use both JScript and VBScript on the same page. Because the server must instantiate and attempt to cache two (rather than one) scripting engines, this increases the system burden to some extent. Therefore, for performance reasons, you should not mix multiple scripting engines on the same page.
26. Question: When we set up an ASP file, and the syntax, enter the following address through the browser, or open browsing through the Explorer: c:\inetpub\wwwroot\ A.asp, you will be unable to run the error, and prompted the right or the file is inaccessible, why not run the ASP file properly?
A: This is because the ASP file first requires the site to have the "execute (script)" attribute, and then requires the URL format to enter the address, rather than the DOS format, we need to install and start the Web service platform on the computer, and ensure that the ASP files are stored in the Web server virtual directory, You can browse through HTTP format, enter in the address bar of the browser: "http://Web site name (or site's IP address)/asp file name", after carriage return can see the server executes ASP file result in the browser.
27. Question: What is asp.net? What does it have to do with ASP?
A: Active Server Pages (ASP, Active Server Page) is a relatively simple programming environment in which you can mix HTML, scripting languages, and a small number of components to create server-side Internet applications;
Asp. NET is a powerful programming environment that Microsoft can use to create web-based applications using a variety of high-level languages such as C # and scripting languages, HTML, XML, XSL, and so on. Asp. NET C # as an object-oriented language, in many ways, C # will become Microsoft's Java-like language. C # is one of the most important features of ASP.net development, and Microsoft will develop C # as a strong competitor to Java. This is also Microsoft. An important part of the NET Framework. I think C # is the main tool for Microsoft to beat its opponents in the programming language field.
Asp. NET in object-oriented, database connection, large site applications are better than the ASP program, ASP. NET also offers new features such as built-in object caching and page-result caching, built-in XML support, simple processing of XML datasets, and more fully interactive server control.
Asp. NET is still completely locked in Microsoft's operating system, to really play asp.net potential, you have to use C # or vb.net. Both languages will become the core scripting language of the ASP.net standard.
