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www.giggi.me / code-igniter-v3-giggi / 7a3b96e27988deeebeeff4469f5de3b9fb50918f / . / user_guide / database / fields.html
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Derek Jonesfd93d222008-05-06 15:18:50 +0000[diff] [blame]6<title>Field Data : CodeIgniter User Guide</title>
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]7
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Derek Jones6b7b11f2008-05-06 16:07:27 +0000[diff] [blame]31<td><h1>CodeIgniter User Guide Version 1.6.2</h1></td>
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adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]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>
Derek Allardbc030912007-06-24 18:25:29 +0000[diff] [blame]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>
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51
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57<div id="content">
58
59
60<h1>Field Data</h1>
61
62
admin194b8942006-10-04 07:59:32 +0000[diff] [blame]63<h2>$this->db->list_fields()</h2>
adminab4f61b2006-09-25 22:12:32 +0000[diff] [blame]64<p>Returns an array containing the field names. This query can be called two ways:</p>
65
66
67<p>1. You can supply the table name and call it from the <dfn>$this->db-></dfn> object:</p>
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]68
69<code>
admin194b8942006-10-04 07:59:32 +0000[diff] [blame]70$fields = $this->db->list_fields('table_name')<br /><br />
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]71
72foreach ($fields as $field)<br />
73{<br />
74&nbsp;&nbsp;&nbsp;echo $field;<br />
75}
76</code>
77
admine334c472006-10-21 19:44:22 +0000[diff] [blame]78<p>2. You can gather the field names associated with any query you run by calling the function
adminab4f61b2006-09-25 22:12:32 +0000[diff] [blame]79from your query result object:</p>
80
81<code>
admin194b8942006-10-04 07:59:32 +0000[diff] [blame]82$query = $this->db->query('SELECT * FROM some_table')
adminab4f61b2006-09-25 22:12:32 +0000[diff] [blame]83<br /><br />
84
admin3dd978f2006-09-30 19:24:45 +0000[diff] [blame]85foreach ($query->list_fields() as $field)<br />
adminab4f61b2006-09-25 22:12:32 +0000[diff] [blame]86{<br />
87&nbsp;&nbsp;&nbsp;echo $field;<br />
88}
89</code>
90
91
admin194b8942006-10-04 07:59:32 +0000[diff] [blame]92<h2>$this->db->field_exists()</h2>
adminb2a9cec2006-10-01 03:38:04 +0000[diff] [blame]93
admine7e1dcd2006-10-21 18:04:01 +0000[diff] [blame]94<p>Sometimes it's helpful to know whether a particular field exists before performing an action.
adminb2a9cec2006-10-01 03:38:04 +0000[diff] [blame]95Returns a boolean TRUE/FALSE. Usage example:</p>
96
97<code>
98if ($this->db->field_exists('field_name', 'table_name'))<br />
99{<br />
100&nbsp;&nbsp; // some code...<br />
101}
102</code>
103
admine334c472006-10-21 19:44:22 +0000[diff] [blame]104<p>Note: Replace <em>field_name</em> with the name of the column you are looking for, and replace
adminb2a9cec2006-10-01 03:38:04 +0000[diff] [blame]105<em>table_name</em> with the name of the table you are looking for.</p>
106
107
108
adminab4f61b2006-09-25 22:12:32 +0000[diff] [blame]109
admin194b8942006-10-04 07:59:32 +0000[diff] [blame]110<h2>$this->db->field_data()</h2>
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]111<p>Returns an array of objects containing field information.</p>
admin3dd978f2006-09-30 19:24:45 +0000[diff] [blame]112<p>Sometimes it's helpful to gather the field names or other metadata, like the column type, max length, etc.</p>
113
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]114
115<p class="important">Note: Not all databases provide meta-data.</p>
116
117<p>Usage example:</p>
118
119<code>
admin194b8942006-10-04 07:59:32 +0000[diff] [blame]120$fields = $this->db->field_data('table_name')<br /><br />
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]121
122foreach ($fields as $field)<br />
123{<br />
124&nbsp;&nbsp;&nbsp;echo $field->name;<br />
125&nbsp;&nbsp;&nbsp;echo $field->type;<br />
126&nbsp;&nbsp;&nbsp;echo $field->max_length;<br />
127&nbsp;&nbsp;&nbsp;echo $field->primary_key;<br />
128}
129</code>
130
admine7e1dcd2006-10-21 18:04:01 +0000[diff] [blame]131<p>If you have run a query already you can use the result object instead of supplying the table name:</p>
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]132
133<code>
admin194b8942006-10-04 07:59:32 +0000[diff] [blame]134$query = $this->db->query("YOUR QUERY")<br />
135$fields = $query->field_data()
adminfb28bb82006-09-24 17:59:33 +0000[diff] [blame]136</code>
137
138
139<p>The following data is available from this function if supported by your database:</p>
140
141<ul>
142<li>name - column name</li>
143<li>max_length - maximum length of the column</li>
144<li>primary_key - 1 if the column is a primary key</li>
145<li>type - the type of the column</li>
146</ul>
147
148
149
150
151
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