| Status | Draft |
|---|---|
| Todo | Needs review |
Database Metadata
Below are methods that provide you with information about fields and tables in the database.
The usual way to call these methods would be from a method in your model, via $this→db.
For example, you might do something like:
$this->db->list_fields('some_table');
<box> Note: Calls to these methods will not show up in the information displayed by the profiler library. </box>
list_fields()
Database::list_fields($table) returns an array of the fields (columns) in the specified table.
- [string] The name of the table to get information for.
field_data()
Database::field_data($table) returns an array, with one entry per field (collumn) in the database. Each entry in this array is an associative sub-array that specifies metadata about a field.
- [string] The name of the table to get information for.
<box> Note: The keys of the sub-array (and the metadata returned about each field) differ depending on the database driver in use. </box>
Using the MySQL driver, each sub-array contains the following keys:
- Field: The name of the field/column this sub-array refers to
- Type: The field/column type, for example „int(10) unsigned”
- Null: Does the field permit NULL values? May either be 'YES' or 'NO'.
- Key: The field's key type. May be empty, or 'PRI' to indicate a primary key field.
- Default: The field's default value for new records.
- Extra: May be empty, or „auto_increment”.
table_exists()
Database::table_exists($table) returns TRUE or FALSE depending on whether the specified table exists in the database.
- [string] The name of the table to check the existence of.
list_tables()
Database::list_tables() returns an array containing the names of all the tables in the database.
