Why Require_Once() Function Is So Bad To Use In Php Include And Require

Why use Comments?

If you don’t work on the source code for some time, it’s easy to lớn forget what the code does.

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Commenting the source code helps remember what the code does. Commenting source code is also very important when multiple developers have sầu to work on the same project. The changes made by one developer can be easily understood by other developers by simply reading the comments. As the best practice, you must have 3 lines of comments for every 10 lines of code

In this tutorial, you will learn-

PHP. Comments

Comments help us lớn understvà the code Comments are explanations that we include in our source code. These comments are for human understanding. Single line comments start with double forward slashes // & they over in the same line. Multiple line comments start with a forward slash followed by the asterisk /* and kết thúc with the asterisk followed by the forward slash */. The diagram below shows a PHP file with both multiple line & single line comments
PHPhường Example PHP Include, Require và Comments

PHP.. Include và PHP.. Include_once

The “include” php statement is used to include other files into a PHP file. It has two variations, include & include_once. Include_once is ignored by the PHPhường interpreter if the tệp tin to be included. The include statement has the following syntax The include_once statement has the following syntax HERE, “Include/include_once” is the statement that includes file “"file_name"” is the name of the tệp tin khổng lồ be included.

Example : Include / Include_once

Suppose you are developing a trang web that contains the same navigation menu across all the pages. You can create a common header then include it in every page using the include statement Let’s see how this can be done. We will create 2 files names header.php, index.php Below are the codes for; header.php HomeAbout usServicesLiên hệ Us index.php The header page above sầu will output

PHPhường Require & PHP require_once

The require statement has two variations, require & require_once. The require/require_once statement is used khổng lồ include tệp tin. Require_once is ignored if the required tệp tin has already been added by any of the four include statements.

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It has the following syntax HERE, “require/require_once” is the statement that includes tệp tin “"file_name"” is the name of the tệp tin khổng lồ be included.

Example : Require

Suppose we are developing a database powered application.
We can create a configuration file that we can include in all pages that connect lớn the database using the require statement. config.php Let’s now look at the sample code that requires the config tệp tin. Pages_Mã Sản Phẩm.php

Php include vs require

The difference between include / require Include Require
Issues a warning when an error occurs Does not issue a warning
Execution of the script continues when an error occurs Execution of the script stops when an error occurs.
Generally, it’s recommended using the include statement so that when an error occurs, execution of the script continues khổng lồ display the webmaster gmail address or the tương tác us page. The require statement should be used if the entire script cannot run without the requested file. The “include” & “require” statements can be used at any line in the source codes where you want the code lớn appear.


Single HTML code such as headers, footers, side bars etc. can be shared across many pages. This makes it easy to lớn update the website by just updating a single file. PHP code such as database configuration settings, custom functions etc. can be shared across many pages ensuring the website/application uses the same settings. Comments are used lớn help underst& source code. They are for human understanding Single line comment statements start with double forward slashes //. Multi-line phản hồi statements are enclosed between /* statements */. The “include, include_once, require & require_once” statements are used to lớn include files. Include_once/require_once is ignored if the requested tệp tin has already been included using any of the four statements. The “include” statement issues a warning and continues with the execution if the requested file has not been found. The require statement raises a fatal error and stops the script execution. The “include” statement should be in most cases except in situations where without the requested tệp tin khổng lồ be include, the entire script cannot run.