This is the second note on asp collation.As long as the most basic questions are figured out,In order to better learn ASP programming.
Question 9:Do I need to use "option explicit" in every asp file?A:In practical applications,The concept of vbscript variables has been blurred,Allow direct use of variables,Instead of declaring variables with dim,But this is not a good habit,Prone to cause program errors,Because it is possible to define a variable repeatedly.We can use the option explicit statement in the program, so when using a variable,It must be declared first,If undeclared variables are used,When running, the program will fail.
Practice has proved thatUsing "option explicit" in an asp file can minimize the chance of program errors.And will greatly improve the overall performance.
Question 10:Are there any security measures when running ASP files?A:ASP provides a good code protection mechanism.All asp code is executed on the server side and only returns the results of the client code execution.But it still does not rule out the malicious destruction of web servers by malicious people,So pay more attention to security issues when writing asp files.
Although files are introduced in asp with asc extension,It is still recommended to use asp as the file extension.When this code runs on a web server with poor security,Just enter the address of the import file (inc is the extension) in the address bar, you can browse the content of the import file,This is because on the web server, if a dynamic link library of a certain type (such as inc) is not defined,The file is displayed in source mode.
Also, don't put database files inside the website structure,In this way, when a malicious person obtains the database path,You can easily get the database,Then wantonly change the contents of the database.A better approach is,Establish a data source name dsn (date source name) for the database, which stores information about connecting to the specified data provider in dsn,Including:"The physical location of the database,The type of driver used to access the database,Any other parameters required by the driver to access the database "can be accessed directly during database access.
Question 11:When reviewing web database management systems,What issues should be considered?A:When evaluating a web database management system,Three issues must be considered:multi-user issues;The established web database should be relational;Database security issues.
Question 12:What is Adobe and how does it operate the database?
Answer:The full name of ado is activex data object (activex data object), which is an optimized set of dedicated objects for accessing the database.It provides a complete site database solution for asp,It acts on the server side,Provide homepage content with database information,By executing the sql command, let the user enter in the browser screen,Update and delete site database information.
Adobe mainly includes three objects:connection, recordset, and command. TheirThe main functionThe following:
Connection object:responsible for opening or connecting to the database file;
Recordset object:access the contents of the database;
Command object:gives action query instructions to the database,And execute the stored procedure of sql server.
Question 13:What is the difference between using a recordset object and a command object to access the database?A:The recordset object will ask the database to transfer all the data.Then when the amount of data is large, it will cause network congestion and overload the database server.Therefore, the overall execution efficiency will decrease.
Use the command object to directly call the SQL statement. The operation performed is performed in the database server.Obviously, there will be high implementation efficiency.In particular, the stored procedure is executed on the server.Can reduce network traffic,In addition, since the parsing was performed in advance,Can improve overall execution efficiency.
Question 14:Do I have to create a connection object for each recordset object?A:You can use the same connection object for different recordset objects at the same time to save resources.
Question 15:What is a database management system (dbms)?A:In order to ensure the security and consistency of the data stored in the database,There must be a set of software to complete the corresponding management tasks,This group of software is a database management system.Referred to as dbms, dbms varies with different systems,But in general,It should include the following aspects:
Database description function:define the global logical structure of the database,Local logical structure and various other database objects;
Database management functions:including system configuration and management,Data access and update management,Data integrity management and data security management;
Database query and manipulation functions:This function includes database retrieval and modification;
Database maintenance functions:including data import and export management,Database structure maintenance,Data recovery functions and performance monitoring.
In order to improve the development efficiency of the database system,In addition to dbms, modern database systems also provide various tools to support application development.
Question 16:What are the current popular web database management systems?A:The current popular web database management systems include Microsoft's SQL Server, Oracle, DB2, and Sybase. Small-scale enterprises often use access.
Today I have organized 8 basic small questions for everyone.Hope everyone can collect it,Really understand every question.
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