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| <h1>Connecting to your Database</h1> |
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| <p>There are two ways to connect to a database:</p> |
| |
| <h2>Automatically Connecting</h2> |
| |
| <p>The "auto connect" feature will load and instantiate the database class with every page load. |
| To enable "auto connecting", add the word <var>database</var> to the library array, as indicated in the following file:</p> |
| |
| <p><kbd>application/config/autoload.php</kbd></p> |
| |
| <h2>Manually Connecting</h2> |
| |
| <p>If only some of your pages require database connectivity you can manually 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.</p> |
| |
| <code>$this->load->database();</code> |
| |
| <p class="important">If the above function does <strong>not</strong> contain any information in the first parameter it will connect |
| to the group specified in your database config file. For most people, this is the preferred method of use.</p> |
| |
| <h3>Available Parameters</h3> |
| |
| <ol> |
| <li>The database connection values, passed either as an array or a DSN string.</li> |
| <li>TRUE/FALSE (boolean). Whether to return the connection ID (see Connecting to Multiple Databases below).</li> |
| <li>TRUE/FALSE (boolean). Whether to enable the Active Record class. Set to TRUE by default.</li> |
| </ol> |
| |
| |
| <h3>Manually Connecting to a Database</h3> |
| |
| <p>The first parameter of this function can <strong>optionally</strong> be used to specify a particular database group |
| from your config file, or you can even submit connection values for a database that is not specified in your config file. |
| Examples:</p> |
| |
| <p>To choose a specific group from your config file you can do this:</p> |
| |
| <code>$this->load->database('<samp>group_name</samp>');</code> |
| |
| <p>Where <samp>group_name</samp> is the name of the connection group from your config file.</p> |
| |
| |
| <p>To connect manually to a desired database you can pass an array of values:</p> |
| |
| <code>$config['hostname'] = "localhost";<br /> |
| $config['username'] = "myusername";<br /> |
| $config['password'] = "mypassword";<br /> |
| $config['database'] = "mydatabase";<br /> |
| $config['dbdriver'] = "mysql";<br /> |
| $config['dbprefix'] = "";<br /> |
| $config['pconnect'] = FALSE;<br /> |
| $config['db_debug'] = TRUE;<br /> |
| $config['cache_on'] = FALSE;<br /> |
| $config['cachedir'] = "";<br /> |
| $config['char_set'] = "utf8";<br /> |
| $config['dbcollat'] = "utf8_general_ci";<br /> |
| <br /> |
| $this->load->database(<samp>$config</samp>);</code> |
| |
| <p>For information on each of these values please see the <a href="configuration.html">configuration page</a>.</p> |
| |
| <p>Or you can submit your database values as a Data Source Name. DSNs must have this prototype:</p> |
| |
| <code>$dsn = 'dbdriver://username:password@hostname/database';<br /> |
| <br /> |
| $this->load->database(<samp>$dsn</samp>);</code> |
| |
| <p>To override default config values when connecting with a DSN string, add the config variables as a query string.</p> |
| |
| <code>$dsn = 'dbdriver://username:password@hostname/database?char_set=utf8&dbcollat=utf8_general_ci&cache_on=true&cachedir=/path/to/cache';<br /> |
| <br /> |
| $this->load->database(<samp>$dsn</samp>);</code> |
| |
| <h2>Connecting to Multiple Databases</h2> |
| |
| <p>If you need to connect to more than one database simultaneously you can do so as follows:</p> |
| |
| |
| <code>$DB1 = $this->load->database('group_one', TRUE);<br /> |
| $DB2 = $this->load->database('group_two', TRUE); |
| </code> |
| |
| <p>Note: Change the words "group_one" and "group_two" to the specific group names you are connecting to (or |
| you can pass the connection values as indicated above).</p> |
| |
| <p>By setting the second parameter to TRUE (boolean) the function will return the database object.</p> |
| |
| <div class="important"> |
| <p>When you connect this way, you will use your object name to issue commands rather than the syntax used throughout this guide. In other words, rather than issuing commands with:</p> |
| |
| <p>$this->db->query();<br />$this->db->result();<br /> etc...</p> |
| |
| <p>You will instead use:</p> |
| |
| <p>$DB1->query();<br />$DB1->result();<br /> etc...</p> |
| |
| </div> |
| |
| <h2>Reconnecting / Keeping the Connection Alive</h2> |
| |
| <p>If the database server's idle timeout is exceeded while you're doing some heavy PHP lifting (processing an image, for instance), you should consider pinging the server by using the <dfn>reconnect()</dfn> method before sending further queries, which can gracefully keep the connection alive or re-establish it.</p> |
| |
| <code>$this->db->reconnect();</code> |
| |
| <h2>Manually closing the Connection</h2> |
| |
| <p>While CodeIgniter intelligently takes care of closing your database connections, you can explicitly close the connection.</p> |
| |
| <code>$this->db->close();</code> |
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