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www.giggi.me / code-igniter-v3-giggi / de78a7d4158152b7197bc74a4ba0dd0d75613042 / . / user_guide / database / queries.html
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45<a href="index.html">Database Library</a> &nbsp;&#8250;&nbsp;
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>
Rick Ellis12abaeb2008-10-17 04:08:03 +0000[diff] [blame]87
88
Derek Allard39b622d2008-01-16 21:10:09 +0000[diff] [blame]89<h1>Protecting identifiers</h1>
Rick Ellis12abaeb2008-10-17 04:08:03 +0000[diff] [blame]90<p>In many databases it is advisable to protect table and field names - for example with backticks in MySQL. <strong>Active Record queries are automatically protected</strong>, however if you need to manually protect an identifier you can use:</p>
Derek Jonesaf368e12008-02-25 21:43:26 +0000[diff] [blame]91<p><code>$this-&gt;db-&gt;protect_identifiers('table_name');</code></p>
Rick Ellis12abaeb2008-10-17 04:08:03 +0000[diff] [blame]92
93<p>This function will also add a table prefix to your table, assuming you have a prefix specified in your database config file. To enable the prefixing set <kbd>TRUE</kbd> (boolen) via the second parameter:</p>
94<p><code>$this-&gt;db-&gt;protect_identifiers('table_name', <kbd>TRUE</kbd>);</code></p>
95
96
admin78ce3cc2006-10-02 02:58:03 +0000[diff] [blame]97<h1>Escaping Queries</h1>
admine334c472006-10-21 19:44:22 +0000[diff] [blame]98<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]99CodeIgniter has two functions that help you do this:</p>
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]100
101<ol>
admine334c472006-10-21 19:44:22 +0000[diff] [blame]102<li><strong>$this->db->escape()</strong> This function determines the data type so that it
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]103can escape only string data. It also automatically adds single quotes around the data so you don't have to:
104
Derek Allardc6441282007-07-04 23:54:32 +0000[diff] [blame]105<code>$sql = "INSERT INTO table (title) VALUES(".$this->db->escape($title).")";</code></li>
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]106
admine334c472006-10-21 19:44:22 +0000[diff] [blame]107<li><strong>$this->db->escape_str()</strong> This function escapes the data passed to it, regardless of type.
Derek Allardcb36e342008-08-31 14:24:56 +0000[diff] [blame]108Most of the time you'll use the above function rather than this one. Use the function like this:
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]109
Derek Allardc6441282007-07-04 23:54:32 +0000[diff] [blame]110<code>$sql = "INSERT INTO table (title) VALUES('".$this->db->escape_str($title)."')";</code></li>
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]111</ol>
112
113
admin78ce3cc2006-10-02 02:58:03 +0000[diff] [blame]114<h1>Query Bindings</h1>
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]115
116
117<p>Bindings enable you to simplify your query syntax by letting the system put the queries together for you. Consider the following example:</p>
118
119<code>
120$sql = "SELECT * FROM some_table WHERE id = <var>?</var> AND status = <var>?</var> AND author = <var>?</var>";
121<br /><br />
122$this->db->query($sql, array(3, 'live', 'Rick'));
123</code>
124
125<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>
126<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>
127
128
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Derek Allardc6441282007-07-04 23:54:32 +0000[diff] [blame]141</p>
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