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This page provides an example of how to create a configuration entity type with administrative management pages in Drupal 8. For an introduction to the concepts of simple configuration and configuration entities, see https://drupal.org/node/2120523.
After enabling the example module that contains the code below, the configuration form should be available at “admin/config/system/example”, as shown in the screenshot:
Using $config in the Context of a Form
This page describes the API for retrieving and setting configuration data for simple configuration. (This does not apply to information stored in configuration objects.)
Using $config in the Context of a Form
You can use configuration forms to see how $config can retrieve user-entered data and update information in the {module}.settings.yml file. Here's the code to declare a $config object within a form, typically found in a PHP settings form file.
The Drupal 8 Database API provides a standardized, vendor-independent abstraction layer for accessing database servers. You should almost never make direct database calls unless you are developing core APIs.
The API is designed to preserve the syntax and power of SQL as much as possible, while also:
The Drupal database layer is built on top of the PHP PDO library. PDO provides a unified, object-oriented API for accessing various databases, but it does not offer abstraction for the different SQL dialects used by different database systems.
The primary way to define a database connection in Drupal is through the $databases array in settings.php. As the name suggests, $databases allows you to define multiple database connections. It also supports defining multiple targets. A connection to the database is not opened (i.e., the connection object is not created) until the first piece of code attempts to run a query against that database.
Connection Key
Interaction with the database should be done through the database connection object. There are several scenarios that require attention:
1. In procedural code, i.e., *.module, *.inc, or script files:
The best way to instantiate the database connection object is via the Service Container.
Example:
The most common SELECT queries in Drupal are static queries using the query() method of the database connection object.
Static queries are passed to the database almost verbatim.
Example:
To create a Drupal 8 theme, you must first create a THEMENAME.info.yml file that provides metadata about your theme in Drupal. This is similar to how modules and installation profiles are defined, so it's important to set the "type" key in the file.info.yml as "theme" to differentiate it.
This page contains an example of a THEMENAME.info.yml file and an overview of the information it may contain.