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CodeIgniter Reactor / user_guide / database / fields.html

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Field Names
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<h1>Field Data</h1>

<p>Returns an array containing the field names. This query can be called two ways:</p>

<p>1. You can supply the table name and call it from the <dfn>$this->db-></dfn> object:</p>

$fields = $this->db->list_fields('table_name');<br /><br />

foreach ($fields as $field)<br />
{<br />
&nbsp;&nbsp;&nbsp;echo $field;<br />

<p>2. You can gather the field names associated with any query you run by calling the function
from your query result object:</p>

$query = $this->db->query('SELECT * FROM some_table');
<br /><br />

foreach ($query->list_fields() as $field)<br />
{<br />
&nbsp;&nbsp;&nbsp;echo $field;<br />


<p>Sometimes it's helpful to know whether a particular field exists before performing an action.
Returns a boolean TRUE/FALSE. Usage example:</p>

if ($this->db->field_exists('field_name', 'table_name'))<br />
{<br />
&nbsp;&nbsp; // some code...<br />

<p>Note: Replace <em>field_name</em> with the name of the column you are looking for, and replace
<em>table_name</em> with the name of the table you are looking for.</p>

<p>Returns an array of objects containing field information.</p>
<p>Sometimes it's helpful to gather the field names or other metadata, like the column type, max length, etc.</p>

<p class="important">Note: Not all databases provide meta-data.</p>

<p>Usage example:</p>

$fields = $this->db->field_data('table_name');<br /><br />

foreach ($fields as $field)<br />
{<br />
&nbsp;&nbsp;&nbsp;echo $field->name;<br />
&nbsp;&nbsp;&nbsp;echo $field->type;<br />
&nbsp;&nbsp;&nbsp;echo $field->max_length;<br />
&nbsp;&nbsp;&nbsp;echo $field->primary_key;<br />

<p>If you have run a query already you can use the result object instead of supplying the table name:</p>

$query = $this->db->query("YOUR QUERY");<br />
$fields = $query->field_data();

<p>The following data is available from this function if supported by your database:</p>

<li>name - column name</li>
<li>max_length - maximum length of the column</li>
<li>primary_key - 1 if the column is a primary key</li>
<li>type - the type of the column</li>

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