Connecting to your Database
You can connect to your database by adding this line of code in any function where it is needed, or in your class constructor to make the database available globally in that class.
<?php $db = \Config\Database::connect();
If the above function does not contain any information in the first parameter, it will connect to the default group specified in your database config file. For most people, this is the preferred method of use.
A convenience method exists that is purely a wrapper around the above line and is provided for your convenience:
<?php $db = db_connect();
\Config\Database::connect($group = null, bool $getShared = true): BaseConnection
$group: The database group name, a string that must match the config class’ property name. Default value is
$getShared: true/false (boolean). Whether to return the shared connection (see Connecting to Multiple Databases below).
The first parameter of this function can optionally be used to specify a particular database group from your config file. Examples:
To choose a specific group from your config file you can do this:
<?php $db = \Config\Database::connect('group_name');
Where group_name is the name of the connection group from your config file.
By default, the
connect() method will return the same instance of the
database connection every time. If you need to have a separate connection
to the same database, send
false as the second parameter:
<?php $db = \Config\Database::connect('group_name', false);
If you need to connect to more than one database simultaneously you can do so as follows:
<?php $db1 = \Config\Database::connect('group_one'); $db2 = \Config\Database::connect('group_two');
Note: Change the words
group_two to the specific
group names you are connecting to.
You don’t need to create separate database configurations if you
only need to use a different database on the same connection. You
can switch to a different database when you need to, like this:
You can pass in an array of database settings instead of a group name to get a connection that uses your custom settings. The array passed in must be the same format as the groups are defined in the configuration file:
<?php $custom = [ 'DSN' => '', 'hostname' => 'localhost', 'username' => '', 'password' => '', 'database' => '', 'DBDriver' => 'MySQLi', 'DBPrefix' => '', 'pConnect' => false, 'DBDebug' => true, 'charset' => 'utf8', 'DBCollat' => 'utf8_general_ci', 'swapPre' => '', 'encrypt' => false, 'compress' => false, 'strictOn' => false, 'failover' => , 'port' => 3306, ]; $db = \Config\Database::connect($custom);
If the database server’s idle timeout is exceeded while you’re doing
some heavy PHP lifting (processing an image, for instance), you should
consider pinging the server by using the
reconnect() method before
sending further queries, which can gracefully keep the connection alive
or re-establish it.
If you are using MySQLi database driver, the
does not ping the server but it closes the connection then connects again.
While CodeIgniter intelligently takes care of closing your database connections, you can explicitly close the connection.