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31 | <td><h1>CodeIgniter User Guide Version 2.1.3</h1></td> | |
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43 | <a href="http://codeigniter.com/">CodeIgniter Home</a> › | |
44 | <a href="../index.html">User Guide Home</a> › | |
45 | <a href="index.html">Database Library</a> › | |
46 | Connecting | |
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54 | <br clear="all" /> | |
55 | ||
56 | ||
57 | <!-- START CONTENT --> | |
58 | <div id="content"> | |
59 | ||
60 | ||
61 | <h1>Connecting to your Database</h1> | |
62 | ||
63 | <p>There are two ways to connect to a database:</p> | |
64 | ||
65 | <h2>Automatically Connecting</h2> | |
66 | ||
67 | <p>The "auto connect" feature will load and instantiate the database class with every page load. | |
68 | To enable "auto connecting", add the word <var>database</var> to the library array, as indicated in the following file:</p> | |
69 | ||
70 | <p><kbd>application/config/autoload.php</kbd></p> | |
71 | ||
72 | <h2>Manually Connecting</h2> | |
73 | ||
74 | <p>If only some of your pages require database connectivity you can manually connect to your database by adding this | |
75 | line of code in any function where it is needed, or in your class constructor to make the database | |
76 | available globally in that class.</p> | |
77 | ||
78 | <code>$this->load->database();</code> | |
79 | ||
80 | <p class="important">If the above function does <strong>not</strong> contain any information in the first parameter it will connect | |
81 | to the group specified in your database config file. For most people, this is the preferred method of use.</p> | |
82 | ||
83 | <h3>Available Parameters</h3> | |
84 | ||
85 | <ol> | |
86 | <li>The database connection values, passed either as an array or a DSN string.</li> | |
87 | <li>TRUE/FALSE (boolean). Whether to return the connection ID (see Connecting to Multiple Databases below).</li> | |
88 | <li>TRUE/FALSE (boolean). Whether to enable the Active Record class. Set to TRUE by default.</li> | |
89 | </ol> | |
90 | ||
91 | ||
92 | <h3>Manually Connecting to a Database</h3> | |
93 | ||
94 | <p>The first parameter of this function can <strong>optionally</strong> be used to specify a particular database group | |
95 | from your config file, or you can even submit connection values for a database that is not specified in your config file. | |
96 | Examples:</p> | |
97 | ||
98 | <p>To choose a specific group from your config file you can do this:</p> | |
99 | ||
100 | <code>$this->load->database('<samp>group_name</samp>');</code> | |
101 | ||
102 | <p>Where <samp>group_name</samp> is the name of the connection group from your config file.</p> | |
103 | ||
104 | ||
105 | <p>To connect manually to a desired database you can pass an array of values:</p> | |
106 | ||
107 | <code>$config['hostname'] = "localhost";<br /> | |
108 | $config['username'] = "myusername";<br /> | |
109 | $config['password'] = "mypassword";<br /> | |
110 | $config['database'] = "mydatabase";<br /> | |
111 | $config['dbdriver'] = "mysql";<br /> | |
112 | $config['dbprefix'] = "";<br /> | |
113 | $config['pconnect'] = FALSE;<br /> | |
114 | $config['db_debug'] = TRUE;<br /> | |
115 | $config['cache_on'] = FALSE;<br /> | |
116 | $config['cachedir'] = "";<br /> | |
117 | $config['char_set'] = "utf8";<br /> | |
118 | $config['dbcollat'] = "utf8_general_ci";<br /> | |
119 | <br /> | |
120 | $this->load->database(<samp>$config</samp>);</code> | |
121 | ||
122 | <p>For information on each of these values please see the <a href="configuration.html">configuration page</a>.</p> | |
123 | ||
124 | <p>Or you can submit your database values as a Data Source Name. DSNs must have this prototype:</p> | |
125 | ||
126 | <code>$dsn = 'dbdriver://username:password@hostname/database';<br /> | |
127 | <br /> | |
128 | $this->load->database(<samp>$dsn</samp>);</code> | |
129 | ||
130 | <p>To override default config values when connecting with a DSN string, add the config variables as a query string.</p> | |
131 | ||
132 | <code>$dsn = 'dbdriver://username:password@hostname/database?char_set=utf8&dbcollat=utf8_general_ci&cache_on=true&cachedir=/path/to/cache';<br /> | |
133 | <br /> | |
134 | $this->load->database(<samp>$dsn</samp>);</code> | |
135 | ||
136 | <h2>Connecting to Multiple Databases</h2> | |
137 | ||
138 | <p>If you need to connect to more than one database simultaneously you can do so as follows:</p> | |
139 | ||
140 | ||
141 | <code>$DB1 = $this->load->database('group_one', TRUE);<br /> | |
142 | $DB2 = $this->load->database('group_two', TRUE); | |
143 | </code> | |
144 | ||
145 | <p>Note: Change the words "group_one" and "group_two" to the specific group names you are connecting to (or | |
146 | you can pass the connection values as indicated above).</p> | |
147 | ||
148 | <p>By setting the second parameter to TRUE (boolean) the function will return the database object.</p> | |
149 | ||
150 | <div class="important"> | |
151 | <p>When you connect this way, you will use your object name to issue commands rather than the syntax used throughout this guide. In other words, rather than issuing commands with:</p> | |
152 | ||
153 | <p>$this->db->query();<br />$this->db->result();<br /> etc...</p> | |
154 | ||
155 | <p>You will instead use:</p> | |
156 | ||
157 | <p>$DB1->query();<br />$DB1->result();<br /> etc...</p> | |
158 | ||
159 | </div> | |
160 | ||
161 | <h2>Reconnecting / Keeping the Connection Alive</h2> | |
162 | ||
163 | <p>If the database server's idle timeout is exceeded while you're doing some heavy PHP lifting (processing an image, for instance), you should consider pinging the server by using the <dfn>reconnect()</dfn> method before sending further queries, which can gracefully keep the connection alive or re-establish it.</p> | |
164 | ||
165 | <code>$this->db->reconnect();</code> | |
166 | ||
167 | <h2>Manually closing the Connection</h2> | |
168 | ||
169 | <p>While CodeIgniter intelligently takes care of closing your database connections, you can explicitly close the connection.</p> | |
170 | ||
171 | <code>$this->db->close();</code> | |
172 | </div> | |
173 | <!-- END CONTENT --> | |
174 | ||
175 | ||
176 | <div id="footer"> | |
177 | <p> | |
178 | Previous Topic: <a href="configuration.html">Database Configuration</a> | |
179 | · | |
180 | <a href="#top">Top of Page</a> · | |
181 | <a href="../index.html">User Guide Home</a> · | |
182 | Next Topic: <a href="queries.html">Queries</a> | |
183 | </p> | |
184 | <p><a href="http://codeigniter.com">CodeIgniter</a> · Copyright © 2006 - 2012 · <a href="http://ellislab.com/">EllisLab, Inc.</a></p> | |
185 | </div> | |
186 | ||
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188 | </html> |