Dtjytyk

I am very new to Magento, i created a CRUD custom module, when I input some data in form, and hit save button, I got an error like this:

Fatal error: Uncaught Error: Undefined class constant 'CACHE_TAG' in
C:xampphtdocstest-localappcodeTestingSimpleNewsModelNews.php:9
Stack trace: #0 C:xampphtdocstest-localvendormagentoframeworkAppCacheTagStrategyIdentifier.php(25):TestingSimpleNewModeNews->getIdentities() 
#1 C:xampphtdocstest-localvendormagentoframeworkAppCacheTagResolver.php(43): MagentoFrameworkAppCacheTagStrategyIdentifier->getTags(Object(TestingSimpleNewsModelNews)) 
#2 C:xampphtdocstest-localvendormagentomodule-page-cacheObserverFlushCacheByTags.php(64): MagentoFrameworkAppCacheTagResolver->getTags(Object(TestingSimpleNewsModelNews)) 
#3 C:xampphtdocstest-localvendormagentoframeworkEventInvokerInvokerDefault.php(72): MagentoPageCacheObserverFlushCacheByTags->execute(Object(MagentoFrameworkEventObserver)) 
#4 C:xampphtdocstest-localvendormagentoframeworkEventInvokerInvokerDefault.php(60): MagentoFrameworkEventInvokerInvokerDefault->_callObserverMethod(Object(Magento in C:xampphtdocstest-localappcodeTestingSimpleNewsModelNews.php on line 9

This is my htdocstest-localappcodeTestingSimpleNewsModelNews.php code:

<?php

namespace TestingSimpleNewsModel;

class News extends MagentoFrameworkModelAbstractModel implements MagentoFrameworkDataObjectIdentityInterface

 public function getIdentities()
 
 return [self::CACHE_TAG . '_' . $this->getId()];
 

 public function getDefaultValues()
 
 $values = [];

 return $values;
 

 /**
 * Define resource model
 */
 protected function _construct()
 
 $this->_init('TestingSimpleNewsModelResourceNews');
 

In the function getIdentities() in your class you can see that the class constant CACHE_TAG is being used. You can read all about class constants here:

I would suggest defining it at the top of your class, this cache tag let's magento know where to store cached data. An example would be:

namespace TestingSimpleNewsModel;

class News extends MagentoFrameworkModelAbstractModel implements MagentoFrameworkDataObjectIdentityInterface

 const CACHE_TAG = 'TESTING_SIMPLE_NEWS';

 public function getIdentities()
 
 return [self::CACHE_TAG . '_' . $this->getId()];
 

 public function getDefaultValues()
 
 $values = [];

 return $values;
 

 /**
 * Define resource model
 */
 protected function _construct()
 
 $this->_init('TestingSimpleNewsModelResourceNews');