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268 lines
8.3 KiB
PHP
268 lines
8.3 KiB
PHP
<?php
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/**
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* @link http://www.yiiframework.com/
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* @copyright Copyright (c) 2008 Yii Software LLC
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* @license http://www.yiiframework.com/license/
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*/
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namespace yii\db;
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use yii\base\InvalidCallException;
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/**
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* DataReader represents a forward-only stream of rows from a query result set.
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*
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* To read the current row of data, call [[read()]]. The method [[readAll()]]
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* returns all the rows in a single array. Rows of data can also be read by
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* iterating through the reader. For example,
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*
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* ```php
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* $command = $connection->createCommand('SELECT * FROM post');
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* $reader = $command->query();
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*
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* while ($row = $reader->read()) {
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* $rows[] = $row;
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* }
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*
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* // equivalent to:
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* foreach ($reader as $row) {
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* $rows[] = $row;
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* }
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*
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* // equivalent to:
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* $rows = $reader->readAll();
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* ```
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*
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* Note that since DataReader is a forward-only stream, you can only traverse it once.
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* Doing it the second time will throw an exception.
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*
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* It is possible to use a specific mode of data fetching by setting
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* [[fetchMode]]. See the [PHP manual](http://www.php.net/manual/en/function.PDOStatement-setFetchMode.php)
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* for more details about possible fetch mode.
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*
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* @property int $columnCount The number of columns in the result set. This property is read-only.
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* @property int $fetchMode Fetch mode. This property is write-only.
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* @property bool $isClosed Whether the reader is closed or not. This property is read-only.
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* @property int $rowCount Number of rows contained in the result. This property is read-only.
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*
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* @author Qiang Xue <qiang.xue@gmail.com>
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* @since 2.0
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*/
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class DataReader extends \yii\base\Object implements \Iterator, \Countable
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{
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/**
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* @var \PDOStatement the PDOStatement associated with the command
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*/
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private $_statement;
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private $_closed = false;
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private $_row;
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private $_index = -1;
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/**
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* Constructor.
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* @param Command $command the command generating the query result
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* @param array $config name-value pairs that will be used to initialize the object properties
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*/
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public function __construct(Command $command, $config = [])
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{
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$this->_statement = $command->pdoStatement;
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$this->_statement->setFetchMode(\PDO::FETCH_ASSOC);
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parent::__construct($config);
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}
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/**
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* Binds a column to a PHP variable.
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* When rows of data are being fetched, the corresponding column value
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* will be set in the variable. Note, the fetch mode must include PDO::FETCH_BOUND.
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* @param int|string $column Number of the column (1-indexed) or name of the column
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* in the result set. If using the column name, be aware that the name
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* should match the case of the column, as returned by the driver.
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* @param mixed $value Name of the PHP variable to which the column will be bound.
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* @param int $dataType Data type of the parameter
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* @see http://www.php.net/manual/en/function.PDOStatement-bindColumn.php
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*/
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public function bindColumn($column, &$value, $dataType = null)
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{
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if ($dataType === null) {
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$this->_statement->bindColumn($column, $value);
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} else {
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$this->_statement->bindColumn($column, $value, $dataType);
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}
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}
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/**
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* Set the default fetch mode for this statement
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* @param int $mode fetch mode
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* @see http://www.php.net/manual/en/function.PDOStatement-setFetchMode.php
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*/
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public function setFetchMode($mode)
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{
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$params = func_get_args();
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call_user_func_array([$this->_statement, 'setFetchMode'], $params);
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}
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/**
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* Advances the reader to the next row in a result set.
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* @return array the current row, false if no more row available
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*/
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public function read()
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{
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return $this->_statement->fetch();
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}
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/**
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* Returns a single column from the next row of a result set.
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* @param int $columnIndex zero-based column index
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* @return mixed the column of the current row, false if no more rows available
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*/
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public function readColumn($columnIndex)
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{
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return $this->_statement->fetchColumn($columnIndex);
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}
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/**
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* Returns an object populated with the next row of data.
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* @param string $className class name of the object to be created and populated
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* @param array $fields Elements of this array are passed to the constructor
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* @return mixed the populated object, false if no more row of data available
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*/
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public function readObject($className, $fields)
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{
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return $this->_statement->fetchObject($className, $fields);
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}
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/**
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* Reads the whole result set into an array.
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* @return array the result set (each array element represents a row of data).
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* An empty array will be returned if the result contains no row.
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*/
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public function readAll()
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{
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return $this->_statement->fetchAll();
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}
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/**
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* Advances the reader to the next result when reading the results of a batch of statements.
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* This method is only useful when there are multiple result sets
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* returned by the query. Not all DBMS support this feature.
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* @return bool Returns true on success or false on failure.
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*/
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public function nextResult()
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{
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if (($result = $this->_statement->nextRowset()) !== false) {
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$this->_index = -1;
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}
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return $result;
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}
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/**
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* Closes the reader.
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* This frees up the resources allocated for executing this SQL statement.
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* Read attempts after this method call are unpredictable.
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*/
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public function close()
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{
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$this->_statement->closeCursor();
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$this->_closed = true;
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}
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/**
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* whether the reader is closed or not.
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* @return bool whether the reader is closed or not.
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*/
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public function getIsClosed()
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{
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return $this->_closed;
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}
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/**
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* Returns the number of rows in the result set.
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* Note, most DBMS may not give a meaningful count.
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* In this case, use "SELECT COUNT(*) FROM tableName" to obtain the number of rows.
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* @return int number of rows contained in the result.
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*/
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public function getRowCount()
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{
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return $this->_statement->rowCount();
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}
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/**
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* Returns the number of rows in the result set.
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* This method is required by the Countable interface.
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* Note, most DBMS may not give a meaningful count.
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* In this case, use "SELECT COUNT(*) FROM tableName" to obtain the number of rows.
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* @return int number of rows contained in the result.
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*/
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public function count()
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{
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return $this->getRowCount();
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}
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/**
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* Returns the number of columns in the result set.
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* Note, even there's no row in the reader, this still gives correct column number.
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* @return int the number of columns in the result set.
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*/
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public function getColumnCount()
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{
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return $this->_statement->columnCount();
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}
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/**
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* Resets the iterator to the initial state.
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* This method is required by the interface [[\Iterator]].
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* @throws InvalidCallException if this method is invoked twice
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*/
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public function rewind()
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{
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if ($this->_index < 0) {
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$this->_row = $this->_statement->fetch();
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$this->_index = 0;
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} else {
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throw new InvalidCallException('DataReader cannot rewind. It is a forward-only reader.');
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}
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}
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/**
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* Returns the index of the current row.
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* This method is required by the interface [[\Iterator]].
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* @return int the index of the current row.
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*/
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public function key()
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{
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return $this->_index;
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}
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/**
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* Returns the current row.
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* This method is required by the interface [[\Iterator]].
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* @return mixed the current row.
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*/
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public function current()
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{
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return $this->_row;
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}
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/**
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* Moves the internal pointer to the next row.
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* This method is required by the interface [[\Iterator]].
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*/
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public function next()
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{
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$this->_row = $this->_statement->fetch();
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$this->_index++;
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}
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/**
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* Returns whether there is a row of data at current position.
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* This method is required by the interface [[\Iterator]].
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* @return bool whether there is a row of data at current position.
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*/
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public function valid()
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{
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return $this->_row !== false;
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}
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}
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