PHP | DOMDocument relaxNGValidate() Function

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The DOMDocument::relaxNGValidate() function is an inbuilt function in PHP which is used to performs relaxNG validation on the document. The relaxNG is an alternative to DDT and defines a structure which needs to be followed by the XML document.

Syntax:

bool DOMDocument::relaxNGValidate( string $filename )

Parameters: This function accepts a single parameter $filename which holds the RNG file.

Return Value: This function returns TRUE on success or FALSE on failure.

Below given programs illustrate the DOMDocument::relaxNGValidate() function in PHP:

Program 1:

File name: rule.rng

<element name="college" 
  xmlns="http://relaxng.org/ns/structure/1.0"> 
  <zeroOrMore> 
    <element name="rollno"> 
      <element name="name"> 
        <text/> 
      </element> 
      <element name="subject"> 
        <text/> 
      </element> 
    </element> 
  </zeroOrMore> 
</element> 

File name: index.php

<?php 
  
// Create a new DOMDocument 
$doc = new DOMDocument; 
  
// Load the XML 
$doc->loadXML("<?xml version=\"1.0\"?> 
<college> 
  <rollno> 
    <name>John Smith</name> 
    <subject>Web</subject> 
  </rollno> 
  <rollno> 
    <name>John Doe</name> 
    <subject>CSE</subject> 
  </rollno> 
</college>"); 
  
// Check if XML follows the relaxNG rule 
if ($doc->relaxNGValidate('rule.rng')) { 
    echo "This document is valid!\n"; 
} 
?> 

Output:
```
This document is valid!
```

Program 2:

File name: rule.rng

<element name="company" 
  xmlns="http://relaxng.org/ns/structure/1.0"> 
  <zeroOrMore> 
    <element name="employee"> 
      <element name="name"> 
        <text/> 
      </element> 
      <element name="salary"> 
        <text/> 
      </element> 
    </element> 
  </zeroOrMore> 
</element> 

File name: index.php

<?php 
  
// Create a new DOMDocument 
$doc = new DOMDocument; 
  
// Load the XML 
$doc->loadXML("<?xml version=\"1.0\"?> 
<company> 
  <employee> 
    <name>John Smith</name> 
    <salary>Web</salary> 
  </employee> 
  <employee> 
    <!-- Do not add salary to voilate rule --> 
    <name>John Doe</name> 
  </employee> 
</company>"); 
  
// Check if XML doesn't follows the relaxNG rule 
if (!$doc->relaxNGValidate('rule.rng')) { 
    echo "This document is not valid!\n"; 
} 
?> 