interface StatementInterface

interface StatementInterface extends \Traversable {
    
    /**
     * Constructs a new PDOStatement object.
     *
     * The PDO manual does not document this constructor, but when overriding the
     * PDOStatement class with a custom without this constructor, PDO will throw
     * the internal exception/warning:
     *
     * "PDO::query(): SQLSTATE[HY000]: General error: user-supplied statement does
     *  not accept constructor arguments"
     *
     * PDO enforces that the access type of this constructor must be protected,
     * and lastly, it also enforces that a custom PDOStatement interface (like
     * this) omits the constructor (declaring it results in fatal errors
     * complaining about "the access type must not be public" if it is public, and
     * "the access type must be omitted" if it is protected; i.e., conflicting
     * statements). The access type has to be protected.
     */
    // protected function __construct(Connection $dbh);
    
    /**
     * Executes a prepared statement
     *
     * @param $args
     *   An array of values with as many elements as there are bound parameters in
     *   the SQL statement being executed. This can be NULL.
     * @param $options
     *   An array of options for this query.
     *
     * @return
     *   TRUE on success, or FALSE on failure.
     */
    public function execute($args = [], $options = []);
    
    /**
     * Gets the query string of this statement.
     *
     * @return
     *   The query string, in its form with placeholders.
     */
    public function getQueryString();
    
    /**
     * Returns the number of rows affected by the last SQL statement.
     *
     * @return
     *   The number of rows affected by the last DELETE, INSERT, or UPDATE
     *   statement executed or throws \Drupal\Core\Database\RowCountException
     *   if the last executed statement was SELECT.
     *
     * @throws \Drupal\Core\Database\RowCountException
     */
    public function rowCount();
    
    /**
     * Sets the default fetch mode for this statement.
     *
     * See http://php.net/manual/pdo.constants.php for the definition of the
     * constants used.
     *
     * @param $mode
     *   One of the PDO::FETCH_* constants.
     * @param $a1
     *   An option depending of the fetch mode specified by $mode:
     *   - for PDO::FETCH_COLUMN, the index of the column to fetch
     *   - for PDO::FETCH_CLASS, the name of the class to create
     *   - for PDO::FETCH_INTO, the object to add the data to
     * @param $a2
     *   If $mode is PDO::FETCH_CLASS, the optional arguments to pass to the
     *   constructor.
     */
    public function setFetchMode($mode, $a1 = NULL, $a2 = []);
    
    /**
     * Fetches the next row from a result set.
     *
     * See http://php.net/manual/pdo.constants.php for the definition of the
     * constants used.
     *
     * @param $mode
     *   One of the PDO::FETCH_* constants.
     *   Default to what was specified by setFetchMode().
     * @param $cursor_orientation
     *   Not implemented in all database drivers, don't use.
     * @param $cursor_offset
     *   Not implemented in all database drivers, don't use.
     *
     * @return
     *   A result, formatted according to $mode.
     */
    public function fetch($mode = NULL, $cursor_orientation = NULL, $cursor_offset = NULL);
    
    /**
     * Returns a single field from the next record of a result set.
     *
     * @param $index
     *   The numeric index of the field to return. Defaults to the first field.
     *
     * @return
     *   A single field from the next record, or FALSE if there is no next record.
     */
    public function fetchField($index = 0);
    
    /**
     * Fetches the next row and returns it as an object.
     *
     * The object will be of the class specified by StatementInterface::setFetchMode()
     * or stdClass if not specified.
     */
    public function fetchObject();
    
    /**
     * Fetches the next row and returns it as an associative array.
     *
     * This method corresponds to PDOStatement::fetchObject(), but for associative
     * arrays. For some reason PDOStatement does not have a corresponding array
     * helper method, so one is added.
     *
     * @return
     *   An associative array, or FALSE if there is no next row.
     */
    public function fetchAssoc();
    
    /**
     * Returns an array containing all of the result set rows.
     *
     * @param $mode
     *   One of the PDO::FETCH_* constants.
     * @param $column_index
     *   If $mode is PDO::FETCH_COLUMN, the index of the column to fetch.
     * @param $constructor_arguments
     *   If $mode is PDO::FETCH_CLASS, the arguments to pass to the constructor.
     *
     * @return
     *   An array of results.
     */
    public function fetchAll($mode = NULL, $column_index = NULL, $constructor_arguments = NULL);
    
    /**
     * Returns an entire single column of a result set as an indexed array.
     *
     * Note that this method will run the result set to the end.
     *
     * @param $index
     *   The index of the column number to fetch.
     *
     * @return
     *   An indexed array, or an empty array if there is no result set.
     */
    public function fetchCol($index = 0);
    
    /**
     * Returns the entire result set as a single associative array.
     *
     * This method is only useful for two-column result sets. It will return an
     * associative array where the key is one column from the result set and the
     * value is another field. In most cases, the default of the first two columns
     * is appropriate.
     *
     * Note that this method will run the result set to the end.
     *
     * @param $key_index
     *   The numeric index of the field to use as the array key.
     * @param $value_index
     *   The numeric index of the field to use as the array value.
     *
     * @return
     *   An associative array, or an empty array if there is no result set.
     */
    public function fetchAllKeyed($key_index = 0, $value_index = 1);
    
    /**
     * Returns the result set as an associative array keyed by the given field.
     *
     * If the given key appears multiple times, later records will overwrite
     * earlier ones.
     *
     * @param $key
     *   The name of the field on which to index the array.
     * @param $fetch
     *   The fetchmode to use. If set to PDO::FETCH_ASSOC, PDO::FETCH_NUM, or
     *   PDO::FETCH_BOTH the returned value with be an array of arrays. For any
     *   other value it will be an array of objects. By default, the fetch mode
     *   set for the query will be used.
     *
     * @return
     *   An associative array, or an empty array if there is no result set.
     */
    public function fetchAllAssoc($key, $fetch = NULL);

}