TYPO3 saving Backend content in another database - database

Question

I want to store content from my Backend in another database.
So let's say i have this in my Backend:
How can i save the value (e.g. the float value in the picture) in another database?
The reason why i need this, is, because i have another database, which is being used for some dynamic content loaded onto my Website with PHP.
Hopefully, someone has an idea and can help me :)

Answer 1

I would use either a hook which updates the foreign database with the value which is triggered if something is changed in the TYPO3 backend or I would use a scheduler task / command controller which is triggered by CLI and runs all x minutes and changes the values in the database.

Answer 2

There are several ways to achieve that. I just assume that you want to create relations between the tt_content table of TYPO3 and some external table in a different database or even different storage engine (web-service, file-system, ...).
In that case you could extend the TCA of the tt_content table by an additional property, let's call it external_reference. The backend form then should provide an additional selector field that allows to chose entities of the external data-source.
The following example assumes that your extension key is called my_extension, this has to be adjusted of course to the actual naming.
You can do so by putting the following configuration to your extension in the folder typo3conf/ext/my_extension/Configuration/TCA/Overrides/tt_content.php:
<?php
\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addTCAcolumns(
'tt_content',
[
'external_reference' => [
'exclude' => 1,
'label' => 'External Source',
'config' => [
'type' => 'select',
'items' => [
['-- none --', 0]
],
'itemsProcFunc' => ExternalReferenceSelection::class . '->render',
'default' => 0,
]
],
]
);
\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addToAllTCAtypes(
'tt_content',
'external_reference'
);
Then you have to implement the selector and the retrieval from the external source, like e.g.
<?php
class ExternalReferenceSelection
{
public function render(array $parameters)
{
$references = ExternalReferenceRepository::instance()->findAll();
foreach ($references as $reference) {
$parameters['items'][] = [
$reference->getTitle(),
$reference->getIdentifier()
];
}
}
}
To be able to persist the selected reference, you have to extend the SQL schema of tt_content as well in typo3conf/ext/my_extension/ext_tables.sql
#
# Table structure for table 'tt_content'
#
CREATE TABLE tt_content (
external_reference int(11) unsigned DEFAULT '0' NOT NULL
);
The database schema is updated by invoking the database analyzer in the TYPO3 Install Tool, or by (re-)installing the extension in the Extension Manager.