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src="data:image/gif;base64,R0lGODlhFAAUAJEAAAAAADMzM////wAAACH5BAUUAAIALAAAAAAUABQAAAImlI+py+0PU5gRBRDM3DxbWoXis42X13USOLauUIqnlsaH/eY6UwAAOw==" /> </div> </ul> <hr/> </div> <div role="main" class="document"> <div class="section" id="connecting-to-your-database"> <h1>Connecting to your Database<a class="headerlink" href="#connecting-to-your-database" title="Permalink to this headline">¶</a></h1> <p>There are two ways to connect to a database:</p> <div class="section" id="automatically-connecting"> <h2>Automatically Connecting<a class="headerlink" href="#automatically-connecting" title="Permalink to this headline">¶</a></h2> <p>The “auto connect” feature will load and instantiate the database class with every page load. To enable “auto connecting”, add the word database to the library array, as indicated in the following file:</p> <p>application/config/autoload.php</p> </div> <div class="section" id="manually-connecting"> <h2>Manually Connecting<a class="headerlink" href="#manually-connecting" title="Permalink to this headline">¶</a></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> <div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$this</span><span class="o">-></span><span class="na">load</span><span class="o">-></span><span class="na">database</span><span class="p">();</span> </pre></div> </div> <p>If the above function does <strong>not</strong> contain any information in the first parameter it will connect to the group specified in your database config file. For most people, this is the preferred method of use.</p> <div class="section" id="available-parameters"> <h3>Available Parameters<a class="headerlink" href="#available-parameters" title="Permalink to this headline">¶</a></h3> <ol class="arabic simple"> <li>The database connection values, passed either as an array or a DSN string.</li> <li>TRUE/FALSE (boolean). Whether to return the connection ID (see Connecting to Multiple Databases below).</li> <li>TRUE/FALSE (boolean). Whether to enable the Query Builder class. Set to TRUE by default.</li> </ol> </div> <div class="section" id="manually-connecting-to-a-database"> <h3>Manually Connecting to a Database<a class="headerlink" href="#manually-connecting-to-a-database" title="Permalink to this headline">¶</a></h3> <p>The first parameter of this function can <strong>optionally</strong> be used to specify a particular database group from your config file, or you can even submit connection values for a database that is not specified in your config file. Examples:</p> <p>To choose a specific group from your config file you can do this:</p> <div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$this</span><span class="o">-></span><span class="na">load</span><span class="o">-></span><span class="na">database</span><span class="p">(</span><span class="s1">'group_name'</span><span class="p">);</span> </pre></div> </div> <p>Where group_name 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> <div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$config</span><span class="p">[</span><span class="s1">'hostname'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'localhost'</span><span class="p">;</span> <span class="nv">$config</span><span class="p">[</span><span class="s1">'username'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'myusername'</span><span class="p">;</span> <span class="nv">$config</span><span class="p">[</span><span class="s1">'password'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'mypassword'</span><span class="p">;</span> <span class="nv">$config</span><span class="p">[</span><span class="s1">'database'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'mydatabase'</span><span class="p">;</span> <span class="nv">$config</span><span class="p">[</span><span class="s1">'dbdriver'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'mysqli'</span><span class="p">;</span> <span class="nv">$config</span><span class="p">[</span><span class="s1">'dbprefix'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">''</span><span class="p">;</span> <span class="nv">$config</span><span class="p">[</span><span class="s1">'pconnect'</span><span class="p">]</span> <span class="o">=</span> <span class="k">FALSE</span><span class="p">;</span> <span class="nv">$config</span><span class="p">[</span><span class="s1">'db_debug'</span><span class="p">]</span> <span class="o">=</span> <span class="k">TRUE</span><span class="p">;</span> <span class="nv">$config</span><span class="p">[</span><span class="s1">'cache_on'</span><span class="p">]</span> <span class="o">=</span> <span class="k">FALSE</span><span class="p">;</span> <span class="nv">$config</span><span class="p">[</span><span class="s1">'cachedir'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">''</span><span class="p">;</span> <span class="nv">$config</span><span class="p">[</span><span class="s1">'char_set'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'utf8'</span><span class="p">;</span> <span class="nv">$config</span><span class="p">[</span><span class="s1">'dbcollat'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'utf8_general_ci'</span><span class="p">;</span> <span class="nv">$this</span><span class="o">-></span><span class="na">load</span><span class="o">-></span><span class="na">database</span><span class="p">(</span><span class="nv">$config</span><span class="p">);</span> </pre></div> </div> <p>For information on each of these values please see the <a class="reference internal" href="configuration.html"><em>configuration page</em></a>.</p> <div class="admonition note"> <p class="first admonition-title">Note</p> <p>For the PDO driver, you should use the $config[‘dsn’] setting instead of ‘hostname’ and ‘database’:</p> <div class="last line-block"> <div class="line"><br /></div> <div class="line">$config[‘dsn’] = ‘mysql:host=localhost;dbname=mydatabase’;</div> </div> </div> <p>Or you can submit your database values as a Data Source Name. DSNs must have this prototype:</p> <div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$dsn</span> <span class="o">=</span> <span class="s1">'dbdriver://username:password@hostname/database'</span><span class="p">;</span> <span class="nv">$this</span><span class="o">-></span><span class="na">load</span><span class="o">-></span><span class="na">database</span><span class="p">(</span><span class="nv">$dsn</span><span class="p">);</span> </pre></div> </div> <p>To override default config values when connecting with a DSN string, add the config variables as a query string.</p> <div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$dsn</span> <span class="o">=</span> <span class="s1">'dbdriver://username:password@hostname/database?char_set=utf8&dbcollat=utf8_general_ci&cache_on=true&cachedir=/path/to/cache'</span><span class="p">;</span> <span class="nv">$this</span><span class="o">-></span><span class="na">load</span><span class="o">-></span><span class="na">database</span><span class="p">(</span><span class="nv">$dsn</span><span class="p">);</span> </pre></div> </div> </div> </div> <div class="section" id="connecting-to-multiple-databases"> <h2>Connecting to Multiple Databases<a class="headerlink" href="#connecting-to-multiple-databases" title="Permalink to this headline">¶</a></h2> <p>If you need to connect to more than one database simultaneously you can do so as follows:</p> <div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$DB1</span> <span class="o">=</span> <span class="nv">$this</span><span class="o">-></span><span class="na">load</span><span class="o">-></span><span class="na">database</span><span class="p">(</span><span class="s1">'group_one'</span><span class="p">,</span> <span class="k">TRUE</span><span class="p">);</span> <span class="nv">$DB2</span> <span class="o">=</span> <span class="nv">$this</span><span class="o">-></span><span class="na">load</span><span class="o">-></span><span class="na">database</span><span class="p">(</span><span class="s1">'group_two'</span><span class="p">,</span> <span class="k">TRUE</span><span class="p">);</span> </pre></div> </div> <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="admonition note"> <p class="first admonition-title">Note</p> <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> <div class="last line-block"> <div class="line"><br /></div> <div class="line">$this->db->query();</div> <div class="line">$this->db->result();</div> <div class="line">etc...</div> <div class="line"><br /></div> <div class="line">You will instead use:</div> <div class="line"><br /></div> <div class="line">$DB1->query();</div> <div class="line">$DB1->result();</div> <div class="line">etc...</div> </div> </div> <div class="admonition note"> <p class="first admonition-title">Note</p> <p>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:</p> <div class="last line-block"> <div class="line">$this->db->db_select($database2_name);</div> </div> </div> </div> <div class="section" id="reconnecting-keeping-the-connection-alive"> <h2>Reconnecting / Keeping the Connection Alive<a class="headerlink" href="#reconnecting-keeping-the-connection-alive" title="Permalink to this headline">¶</a></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 reconnect() method before sending further queries, which can gracefully keep the connection alive or re-establish it.</p> <div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$this</span><span class="o">-></span><span class="na">db</span><span class="o">-></span><span class="na">reconnect</span><span class="p">();</span> </pre></div> </div> </div> <div class="section" id="manually-closing-the-connection"> <h2>Manually closing the Connection<a class="headerlink" href="#manually-closing-the-connection" title="Permalink to this headline">¶</a></h2> <p>While CodeIgniter intelligently takes care of closing your database connections, you can explicitly close the connection.</p> <div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$this</span><span class="o">-></span><span class="na">db</span><span class="o">-></span><span class="na">close</span><span class="p">();</span> </pre></div> </div> </div> </div> </div> <footer> <div class="rst-footer-buttons" role="navigation" aria-label="footer navigation"> <a href="queries.html" class="btn btn-neutral float-right" title="Queries">Next <span class="fa fa-arrow-circle-right"></span></a> <a href="configuration.html" class="btn btn-neutral" title="Database Configuration"><span class="fa fa-arrow-circle-left"></span> Previous</a> </div> <hr/> <div role="contentinfo"> <p> © Copyright 2014 - 2017, British Columbia Institute of Technology. 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