user_guide_src/source/database/fields.rst

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Field Data
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$this->db->list_fields()
=========================

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; }

$this->db->field_exists()
==========================

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.

$this->db->field_data()
========================

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