TYPO3 LTS 8 not support datatype JSON

Question

I am using TYPO3 version 8 LTS, I want to alter one column's datatype from text to JSON. Is there any way to do this? I manually changed to JSON but the upgrade wizard shows an error like

Unknown database type JSON requested, Doctrine\\DBAL\\Platforms\\MySQL57Platform may not support it.

Answer 1

Patch to make JSON columns work on TYPO3 v8:

diff --git typo3/sysext/core/Classes/Database/ConnectionPool.php typo3/sysext/core/Classes/Database/ConnectionPool.php
index 5b1adc2a..8f81e615 100644
--- typo3/sysext/core/Classes/Database/ConnectionPool.php
+++ typo3/sysext/core/Classes/Database/ConnectionPool.php
@@ -168,6 +168,7 @@ protected function getDatabaseConnection(array $connectionParams): Connection
         foreach ($this->customDoctrineTypes as $type => $className) {
             $conn->getDatabasePlatform()->registerDoctrineTypeMapping($type, $type);
         }
+        $conn->getDatabasePlatform()->registerDoctrineTypeMapping('json', 'json_array');
 
         // Handler for building custom data type column definitions
         // in the SchemaManager