Documentation/database/field_data.html

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  60         <div class="content">
  61                 <h1>Field Meta Data</h1>
  62
  63                 <p>These are a set of methods that let you retrieve information about fields within a table.</p>
  64         </div>
  65
  66         <div class="content">
  67                 <h1>$this->db->list_fields()</h1>
  68
  69                 <p>This method returns an array containing the names of the fields in the specified table.  There are two ways
  70                 in which you can call this method.</p>
  71
  72                 <ol>
  73                         <li>
  74                                 <p>You can supply the table name and call it from the <b>$this->db</b> object.</p>
  75
  76                                 <div class="example">
  77                                         $fields = $this->db->list_fields('some_table');<br />
  78                                         <br />
  79                                         foreach ($fields as $field)<br />
  80                                         &#123;<br />
  81                                         &nbsp;&nbsp;&nbsp;&nbsp;echo $field;<br />
  82                                         &#125;
  83                                 </div>
  84                         </li>
  85
  86                         <li>
  87                                 <p>You can gather the field names associated with any query that you run.</p>
  88
  89                                 <div class="example">
  90                                         $query = $this->db->query('SELECT * FROM `some_table`');<br />
  91                                         <br />
  92                                         foreach ($query->list_fields() as $field)<br />
  93                                         &#123;<br />
  94                                         &nbsp;&nbsp;&nbsp;&nbsp;echo $field;<br />
  95                                         &#125;
  96                                 </div>
  97                         </li>
  98                 </ol>
  99         </div>
 100
 101         <div class="content">
 102                 <h1>$this->db->field_exists()</h1>
 103
 104                 <p>This method returns whether a field in a table exists or not.</p>
 105
 106                 <div class="example">
 107                         if ($this->db->field_exists('field_name', 'table_name'))<br />
 108                         &#123;<br />
 109                         &nbsp;&nbsp;&nbsp;&nbsp;// Execute some code...<br />
 110                         &#125;
 111                 </div>
 112         </div>
 113
 114         <div class="content">
 115                 <h1>$this->db->field_data()</h1>
 116
 117                 <p>This method returns an array of object containing the information for the specified field.  Sometimes
 118                 it is helpful to gather informatin about field names.</p>
 119
 120                 <div class="example">
 121                         $fields = $this->db->field_data('table_name');<br />
 122                         <br />
 123                         foreach ($fields as $field)<br />
 124                         &#123;<br />
 125                         &nbsp;&nbsp;&nbsp;&nbsp;echo $field->name;<br />
 126                         &nbsp;&nbsp;&nbsp;&nbsp;echo $field->type;<br />
 127                         &nbsp;&nbsp;&nbsp;&nbsp;echo $field->max_length;<br />
 128                         &nbsp;&nbsp;&nbsp;&nbsp;echo $field->primary_key;<br />
 129                         &#125;
 130                 </div>
 131
 132                 <p>If you have run a query already you can use the result object instead of supplying a table name.</p>
 133
 134                 <div class="example">
 135                         $query = $this->db->query('SQL QUERY');<br />
 136                         $fields = $query->field_data();
 137                 </div>
 138
 139                 <p>You can retrieve the following data about the fields.</p>
 140
 141                 <ul>
 142                         <li><b>name</b> - the name of the column.</li>
 143                         <li><b>max_length</b> - the maximum length of the column.</li>
 144                         <li><b>primary_key</b> - returns 1 if the column is a primary key.</li>
 145                         <li><b>type</b> - returns the data type of the column</li>
 146                 </ul>
 147         </div>
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