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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>
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44<a href="index.html">Database Library</a> &nbsp;&#8250;&nbsp;
45Field Names
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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
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Derek Jones7f3719f2010-01-05 13:35:37 +0000[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>
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