To read the current row of data, call DataReader::read. The method DataReader::readAll
returns all the rows in a single array. Rows of data can also be read by
iterating through the reader. For example,
php
$command = $connection->createCommand('SELECT * FROM post');
$reader = $command->query();
while ($row = $reader->read()) {
$rows[] = $row;
}
equivalent to:
foreach ($reader as $row) {
$rows[] = $row;
}
equivalent to:
$rows = $reader->readAll();
Note that since DataReader is a forward-only stream, you can only traverse it once.
Doing it the second time will throw an exception.
It is possible to use a specific mode of data fetching by setting
[[fetchMode]]. See the PHP manual
for more details about possible fetch mode.
/**
* Returns an object populated with the next row of data.
* @param string $className class name of the object to be created and populated
* @param array $fields Elements of this array are passed to the constructor
* @return mixed the populated object, false if no more row of data available
*/
public function readObject($className, $fields)
{
//Try..Catch to prevent Function sequence error: -11067
try {
return parent::readObject($className, $fields);
} catch (\Exception $ex) {
}
return false;
}
/**
* Returns an object populated with the next row of data.
* @param string $className class name of the object to be created and populated
* @param array $fields Elements of this array are passed to the constructor
* @return mixed the populated object, false if no more row of data available
*/
public function readObject($className, $fields)
{
//Try..Catch to prevent CLI0125E Function sequence error. SQLSTATE=HY010
try {
return parent::readObject($className, $fields);
} catch (\Exception $ex) {
}
return false;
}
/**
* Renders next batch of rows.
* @param integer $rowsNumber set to -1 to render all rows
* @return string
*/
public function renderChunk($rowsNumber)
{
/** @var ActiveDataProvider $dataProvider */
$dataProvider = $this->grid->dataProvider;
/** @var \yii\db\ActiveQuery $query */
$query = $dataProvider->query;
$result = '';
if ($this->rowNumber === 0) {
$result .= $this->renderHeader();
}
$rowCount = $this->dataReader->getRowCount();
for ($i = 0; $i < $rowsNumber || $rowsNumber === -1; $i++) {
$row = $this->dataReader->read();
if ($row === false) {
$this->dataReader = null;
$result .= $this->renderFooter();
break;
}
$models = $query->populate([$row]);
$result .= $this->renderRow(reset($models), $this->rowNumber++, $rowCount);
}
return $result;
}