Where does thinkphp read the database configuration information in the Conf/conf. php file?

Where does thinkphp read Conf/conf. the database configuration information in the PHP file has been studied in thinkphp & nbsp; framework for several days, but the database configuration information obtained during Database instantiation cannot be found. & nbsp; & nbsp; 'DB _ type' = & gt; 'mysql', & nbsp; & n where thinkphp reads Conf/conf. database configuration information in the PHP file
I have been studying the thinkphp framework for a few days, but I still cannot find the database configuration information obtained when instantiating the database.
'Db _ type' => 'mysql ',
'Db _ host' => 'localhost ',
'Db _ name' => 'examples ',
'Db _ user' => 'root ',
'Db _ pwd' => '123 ',
'Db _ port' => '123 ',
'Db _ prefix' => 'think _',
Then, return the database instantiation object

Expert analysis
------ Solution --------------------
When instantiating the Think class, call the C function in the Think: buildApp method to load
It is stored in the C function as a static variable.

------ Solution --------------------
$ User = new Model ("User"); // "User" is the name of the database table.
$ User = M ("User"); this is a simple method provided by thinkphp.
$ List = $ user-> select ();
Var_dump ($ list );
Configuration is
Config. inc. php file and
In the controller
$ Arrr = array (
'Dbms '=> 'mysqli', // note that the key name in the group in this book cannot be changed.
'Username' => 'Google ',
'Password' => 'hello ',
'Hostname' => '2017. 0.0.1 ',
'Database' => 'mydbname ',
);
$ Db = new Db ($ arrr );