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Derek Jonesfd93d222008-05-06 15:18:50 +0000[diff] [blame]6<title>Queries : CodeIgniter User Guide</title>
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46Queries
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61
62<h1>Queries</h1>
63
64<h2>$this->db->query();</h2>
65
66<p>To submit a query, use the following function:</p>
67
68<code>$this->db->query('YOUR QUERY HERE');</code>
69
70<p>The <dfn>query()</dfn> function returns a database result <strong>object</strong> when "read" type queries are run,
71which you can use to <a href="results.html">show your results</a>. When "write" type queries are run it simply returns TRUE or FALSE
72depending on success or failure. When retrieving data you will typically assign the query to your own variable, like this:</p>
73
74<code><var>$query</var> = $this->db->query('YOUR QUERY HERE');</code>
75
76<h2>$this->db->simple_query();</h2>
77
78<p>This is a simplified version of the <dfn>$this->db->query()</dfn> function. It ONLY returns TRUE/FALSE on success or failure.
admine334c472006-10-21 19:44:22 +0000[diff] [blame]79It DOES NOT return a database result set, nor does it set the query timer, or compile bind data, or store your query for debugging.
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]80It simply lets you submit a query. Most users will rarely use this function.</p>
81
82
Derek Allard3b118682008-01-22 23:44:32 +0000[diff] [blame]83<h1>Adding Database prefixes manually</h1>
84<p>If you have configured a database prefix and would like to add it in manually for, you can use the following.</p>
85<p><code>$this-&gt;db-&gt;dbprefix('tablename');<br />
86// outputs prefix_tablename</code></p>
Derek Allard39b622d2008-01-16 21:10:09 +0000[diff] [blame]87<h1>Protecting identifiers</h1>
88<p>In many databases it is advisable to protect table and field names - for example with backticks in MySQL. Active Record queries are automatically protected, however if you need to manually protect an identifier you can use:</p>
Derek Jonesaf368e12008-02-25 21:43:26 +0000[diff] [blame]89<p><code>$this-&gt;db-&gt;protect_identifiers('table_name');</code></p>
admin78ce3cc2006-10-02 02:58:03 +0000[diff] [blame]90<h1>Escaping Queries</h1>
admine334c472006-10-21 19:44:22 +0000[diff] [blame]91<p>It's a very good security practice to escape your data before submitting it into your database.
Derek Allardd2df9bc2007-04-15 17:41:17 +0000[diff] [blame]92CodeIgniter has two functions that help you do this:</p>
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]93
94<ol>
admine334c472006-10-21 19:44:22 +0000[diff] [blame]95<li><strong>$this->db->escape()</strong> This function determines the data type so that it
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]96can escape only string data. It also automatically adds single quotes around the data so you don't have to:
97
Derek Allardc6441282007-07-04 23:54:32 +0000[diff] [blame]98<code>$sql = "INSERT INTO table (title) VALUES(".$this->db->escape($title).")";</code></li>
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]99
admine334c472006-10-21 19:44:22 +0000[diff] [blame]100<li><strong>$this->db->escape_str()</strong> This function escapes the data passed to it, regardless of type.
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]101Most of the time you'll use the above function rather then this one. Use the function like this:
102
Derek Allardc6441282007-07-04 23:54:32 +0000[diff] [blame]103<code>$sql = "INSERT INTO table (title) VALUES('".$this->db->escape_str($title)."')";</code></li>
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]104</ol>
105
106
admin78ce3cc2006-10-02 02:58:03 +0000[diff] [blame]107<h1>Query Bindings</h1>
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]108
109
110<p>Bindings enable you to simplify your query syntax by letting the system put the queries together for you. Consider the following example:</p>
111
112<code>
113$sql = "SELECT * FROM some_table WHERE id = <var>?</var> AND status = <var>?</var> AND author = <var>?</var>";
114<br /><br />
115$this->db->query($sql, array(3, 'live', 'Rick'));
116</code>
117
118<p>The question marks in the query are automatically replaced with the values in the array in the second parameter of the query function.</p>
119<p class="important">The secondary benefit of using binds is that the values are automatically escaped, producing safer queries. You don't have to remember to manually escape data; the engine does it automatically for you.</p>
120
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