PHP4 is packed with good features. One of the most popular is session variables. These are variables that persist throughout a session, as the user moves from page to page. Session variables are great holders of state information and other useful stuff.
To use session variables, call session_start() at the beginning of your web page, before your HTTP headers are sent. Then for every variable you want to keep alive for the duration of the session, store it in $_SESSION[$variable_name]. By default, the session handler will keep track of the session by using a cookie. You can save objects or arrays in session variables also (but be warned that this is buggy in some versions of PHP4).
Typical SQL injection happens when user input is not filtered for escape characters and is then passed into a SQL statement. This results in the potential manipulation of the statements performed on the database by the end user of the application.
Open DataBase Connectivity is an Application Programming Interface (API) that allows a programmer to abstract a program from a database. When writing code to interact with a database, you have to add code that talks to a particular database using a proprietary API. If you want your program to talk to an Access, FoxPro and Oracle databases you have to code your program with three different database API's. This can be quite the daunting task causing much grief. Now, enter ODBC...
When programming to interact with ODBC you only need to use the ODBC API (a combination of ODBC extension function calls and the SQL language) to talk to different database products. The ODBC Manager will figure out how to contend with the type of database you are targeting. Regardless of the database type you are using, all of your calls will be to the ODBC API. All that you need to do is have installed an ODBC driver that is specific to the type of database you will be using.
In this article I will try to give a view of what is the custom caching with php, why and how we can use it.
In the modern days, most of the sites are database driven. That means that your site is actually an application which retrieves data from a DBMS ( database managment system, eg MySQL) , parses the data and shows the result to the user. Most of these data are usually don't change frequently or don't change at all, and the reason that we use the database is that we can easilly update the site and the content.
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