如何在Drupal 8中从数据库中写入和读取信息？

Question

I can't write and read informations from the database in Drupal 8.

In Drupal 7 it looked like this:

# save & update
variable_set('variable', 'value');

# get
variable_get('test', false);

I know that in Drupal 8 it looks completely different but enerything I tried does not work.

Answer 1

To read data from a configuration object use \Drupal::config()->get('system.site')->get('name').

To set data to a configuration object you first need to load the editable configuration entity, then set the data and finally save it.

$site_settings = \Drupal::configFactory()->getEditable('system.site');
$site_settings->set('name', 'Foo site');
$site_settings->save();

To save custom configuration to the database, create a configuration yaml file:

modules/MODULE_NAME/config/install/custom.configuration.yml

custom-variable: 'hello world'

You should also probide a schema file for your configurations:

modules/MODULE_NAME/config/schema/custom.configuration.schema.yml

custom-variable:
  type: 'string'
  label: 'Custom variable'
  description: 'A custom variable to store information in the database'