Gitiles
Code Review Sign In
www.giggi.me / code-igniter-v3-giggi / d6d70e327b74018ab1cd59185a0dc970cd0711be / . / user_guide / database / fields.html
blob: 30d39a42dcf5a29854fc14d2797a86c2da6185e1 [file] [log] [blame]
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]1<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
2<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
3<head>
4
5<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
6<title>Field Data : CodeIgniter User Guide</title>
7
8<style type='text/css' media='all'>@import url('../userguide.css');</style>
9<link rel='stylesheet' type='text/css' media='all' href='../userguide.css' />
10
11<script type="text/javascript" src="../nav/nav.js"></script>
12<script type="text/javascript" src="../nav/prototype.lite.js"></script>
13<script type="text/javascript" src="../nav/moo.fx.js"></script>
14<script type="text/javascript" src="../nav/user_guide_menu.js"></script>
15
16<meta http-equiv='expires' content='-1' />
17<meta http-equiv= 'pragma' content='no-cache' />
18<meta name='robots' content='all' />
19<meta name='author' content='ExpressionEngine Dev Team' />
20<meta name='description' content='CodeIgniter User Guide' />
21
22</head>
23<body>
24
25<!-- START NAVIGATION -->
26<div id="nav"><div id="nav_inner"><script type="text/javascript">create_menu('../');</script></div></div>
27<div id="nav2"><a name="top"></a><a href="javascript:void(0);" onclick="myHeight.toggle();"><img src="../images/nav_toggle_darker.jpg" width="154" height="43" border="0" title="Toggle Table of Contents" alt="Toggle Table of Contents" /></a></div>
28<div id="masthead">
29<table cellpadding="0" cellspacing="0" border="0" style="width:100%">
30<tr>
Derek Jones8917af72010-03-05 12:41:45 -0600[diff] [blame]31<td><h1>CodeIgniter User Guide Version 2.0.0</h1></td>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]32<td id="breadcrumb_right"><a href="../toc.html">Table of Contents Page</a></td>
33</tr>
34</table>
35</div>
36<!-- END NAVIGATION -->
37
38<!-- START BREADCRUMB -->
39<table cellpadding="0" cellspacing="0" border="0" style="width:100%">
40<tr>
41<td id="breadcrumb">
42<a href="http://codeigniter.com/">CodeIgniter Home</a> &nbsp;&#8250;&nbsp;
43<a href="../index.html">User Guide Home</a> &nbsp;&#8250;&nbsp;
44<a href="index.html">Database Library</a> &nbsp;&#8250;&nbsp;
45Field Names
46</td>
47<td id="searchbox"><form method="get" action="http://www.google.com/search"><input type="hidden" name="as_sitesearch" id="as_sitesearch" value="codeigniter.com/user_guide/" />Search User Guide&nbsp; <input type="text" class="input" style="width:200px;" name="q" id="q" size="31" maxlength="255" value="" />&nbsp;<input type="submit" class="submit" name="sa" value="Go" /></form></td>
48</tr>
49</table>
50<!-- END BREADCRUMB -->
51
52
53<br clear="all" />
54
55
56<!-- START CONTENT -->
57<div id="content">
58
59
60<h1>Field Data</h1>
61
62
63<h2>$this->db->list_fields()</h2>
64<p>Returns an array containing the field names. This query can be called two ways:</p>
65
66
67<p>1. You can supply the table name and call it from the <dfn>$this->db-></dfn> object:</p>
68
69<code>
70$fields = $this->db->list_fields('table_name');<br /><br />
71
72foreach ($fields as $field)<br />
73{<br />
74&nbsp;&nbsp;&nbsp;echo $field;<br />
75}
76</code>
77
78<p>2. You can gather the field names associated with any query you run by calling the function
79from your query result object:</p>
80
81<code>
82$query = $this->db->query('SELECT * FROM some_table');
83<br /><br />
84
85foreach ($query->list_fields() as $field)<br />
86{<br />
87&nbsp;&nbsp;&nbsp;echo $field;<br />
88}
89</code>
90
91
92<h2>$this->db->field_exists()</h2>
93
94<p>Sometimes it's helpful to know whether a particular field exists before performing an action.
95Returns a boolean TRUE/FALSE. Usage example:</p>
96
97<code>
98if ($this->db->field_exists('field_name', 'table_name'))<br />
99{<br />
100&nbsp;&nbsp; // some code...<br />
101}
102</code>
103
104<p>Note: Replace <em>field_name</em> with the name of the column you are looking for, and replace
105<em>table_name</em> with the name of the table you are looking for.</p>
106
107
108<h2>$this->db->field_data()</h2>
109<p>Returns an array of objects containing field information.</p>
110<p>Sometimes it's helpful to gather the field names or other metadata, like the column type, max length, etc.</p>
111
112
113<p class="important">Note: Not all databases provide meta-data.</p>
114
115<p>Usage example:</p>
116
117<code>
118$fields = $this->db->field_data('table_name');<br /><br />
119
120foreach ($fields as $field)<br />
121{<br />
122&nbsp;&nbsp;&nbsp;echo $field->name;<br />
123&nbsp;&nbsp;&nbsp;echo $field->type;<br />
124&nbsp;&nbsp;&nbsp;echo $field->max_length;<br />
125&nbsp;&nbsp;&nbsp;echo $field->primary_key;<br />
126}
127</code>
128
129<p>If you have run a query already you can use the result object instead of supplying the table name:</p>
130
131<code>
132$query = $this->db->query("YOUR QUERY");<br />
133$fields = $query->field_data();
134</code>
135
136
137<p>The following data is available from this function if supported by your database:</p>
138
139<ul>
140<li>name - column name</li>
141<li>max_length - maximum length of the column</li>
142<li>primary_key - 1 if the column is a primary key</li>
143<li>type - the type of the column</li>
144</ul>
145
146
147</div>
148<!-- END CONTENT -->
149
150
151<div id="footer">
152<p>
153Previous Topic:&nbsp;&nbsp;<a href="table_data.html"> Table Data</a>
154&nbsp;&nbsp;&nbsp;&middot;&nbsp;&nbsp;
155<a href="#top">Top of Page</a>&nbsp;&nbsp;&nbsp;&middot;&nbsp;&nbsp;
156<a href="../index.html">User Guide Home</a>&nbsp;&nbsp;&nbsp;&middot;&nbsp;&nbsp;
157Next Topic:&nbsp;&nbsp;<a href="call_function.html">Custom Function Calls</a>
158</p>
Derek Jonesd6d70e32010-03-29 10:10:27 -0500[diff] [blame^]159<p><a href="http://codeigniter.com">CodeIgniter</a> &nbsp;&middot;&nbsp; Copyright &#169; 2006-2010 &nbsp;&middot;&nbsp; <a href="http://ellislab.com/">EllisLab, Inc.</a></p>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]160</div>
161
162</body>
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]163</html>