Урок - Поле данных.

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CodeIgniter® 2.2

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

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

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

foreach ($fields as $field)
   echo $field;

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

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

foreach ($query->list_fields() as $field)
   echo $field;


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

if ($this->db->field_exists('field_name', 'table_name'))
   // some code...

Note: Replace field_name with the name of the column you are looking for, and replace table_name with the name of the table you are looking for.


Returns an array of objects containing field information.

Sometimes it's helpful to gather the field names or other metadata, like the column type, max length, etc.

Note: Not all databases provide meta-data.

Usage example:

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

foreach ($fields as $field)
   echo $field->name;
   echo $field->type;
   echo $field->max_length;
   echo $field->primary_key;

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

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

The following data is available from this function if supported by your database:

  • name - column name
  • max_length - maximum length of the column
  • primary_key - 1 if the column is a primary key
  • type - the type of the column