Class yii\db\DataReader
Inheritance | yii\db\DataReader » yii\base\BaseObject |
---|---|
Implements | Countable, Iterator, yii\base\Configurable |
Available since version | 2.0 |
Source Code | https://github.com/yiisoft/yii2/blob/master/framework/db/DataReader.php |
DataReader represents a forward-only stream of rows from a query result set.
To read the current row of data, call read(). The method readAll() returns all the rows in a single array. Rows of data can also be read by iterating through the reader. For example,
$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.
Public Properties
Property | Type | Description | Defined By |
---|---|---|---|
$columnCount | integer | The number of columns in the result set. | yii\db\DataReader |
$fetchMode | integer | Fetch mode. | yii\db\DataReader |
$isClosed | boolean | Whether the reader is closed or not. | yii\db\DataReader |
$rowCount | integer | Number of rows contained in the result. | yii\db\DataReader |
Public Methods
Method | Description | Defined By |
---|---|---|
__call() | Calls the named method which is not a class method. | yii\base\BaseObject |
__construct() | Constructor. | yii\db\DataReader |
__get() | Returns the value of an object property. | yii\base\BaseObject |
__isset() | Checks if a property is set, i.e. defined and not null. | yii\base\BaseObject |
__set() | Sets value of an object property. | yii\base\BaseObject |
__unset() | Sets an object property to null. | yii\base\BaseObject |
bindColumn() | Binds a column to a PHP variable. | yii\db\DataReader |
canGetProperty() | Returns a value indicating whether a property can be read. | yii\base\BaseObject |
canSetProperty() | Returns a value indicating whether a property can be set. | yii\base\BaseObject |
className() | Returns the fully qualified name of this class. | yii\base\BaseObject |
close() | Closes the reader. | yii\db\DataReader |
count() | Returns the number of rows in the result set. | yii\db\DataReader |
current() | Returns the current row. | yii\db\DataReader |
getColumnCount() | Returns the number of columns in the result set. | yii\db\DataReader |
getIsClosed() | Whether the reader is closed or not. | yii\db\DataReader |
getRowCount() | Returns the number of rows in the result set. | yii\db\DataReader |
hasMethod() | Returns a value indicating whether a method is defined. | yii\base\BaseObject |
hasProperty() | Returns a value indicating whether a property is defined. | yii\base\BaseObject |
init() | Initializes the object. | yii\base\BaseObject |
key() | Returns the index of the current row. | yii\db\DataReader |
next() | Moves the internal pointer to the next row. | yii\db\DataReader |
nextResult() | Advances the reader to the next result when reading the results of a batch of statements. | yii\db\DataReader |
read() | Advances the reader to the next row in a result set. | yii\db\DataReader |
readAll() | Reads the whole result set into an array. | yii\db\DataReader |
readColumn() | Returns a single column from the next row of a result set. | yii\db\DataReader |
readObject() | Returns an object populated with the next row of data. | yii\db\DataReader |
rewind() | Resets the iterator to the initial state. | yii\db\DataReader |
setFetchMode() | Set the default fetch mode for this statement. | yii\db\DataReader |
valid() | Returns whether there is a row of data at current position. | yii\db\DataReader |
Property Details
The number of columns in the result set.
Method Details
Defined in: yii\base\BaseObject::__call()
Calls the named method which is not a class method.
Do not call this method directly as it is a PHP magic method that will be implicitly called when an unknown method is being invoked.
public mixed __call ( $name, $params ) | ||
$name | string |
The method name |
$params | array |
Method parameters |
return | mixed |
The method return value |
---|---|---|
throws | yii\base\UnknownMethodException |
when calling unknown method |
public function __call($name, $params)
{
throw new UnknownMethodException('Calling unknown method: ' . get_class($this) . "::$name()");
}
Constructor.
public void __construct ( yii\db\Command $command, $config = [] ) | ||
$command | yii\db\Command |
The command generating the query result |
$config | array |
Name-value pairs that will be used to initialize the object properties |
public function __construct(Command $command, $config = [])
{
$this->_statement = $command->pdoStatement;
$this->_statement->setFetchMode(\PDO::FETCH_ASSOC);
parent::__construct($config);
}
Defined in: yii\base\BaseObject::__get()
Returns the value of an object property.
Do not call this method directly as it is a PHP magic method that
will be implicitly called when executing $value = $object->property;
.
See also __set().
public mixed __get ( $name ) | ||
$name | string |
The property name |
return | mixed |
The property value |
---|---|---|
throws | yii\base\UnknownPropertyException |
if the property is not defined |
throws | yii\base\InvalidCallException |
if the property is write-only |
public function __get($name)
{
$getter = 'get' . $name;
if (method_exists($this, $getter)) {
return $this->$getter();
} elseif (method_exists($this, 'set' . $name)) {
throw new InvalidCallException('Getting write-only property: ' . get_class($this) . '::' . $name);
}
throw new UnknownPropertyException('Getting unknown property: ' . get_class($this) . '::' . $name);
}
Defined in: yii\base\BaseObject::__isset()
Checks if a property is set, i.e. defined and not null.
Do not call this method directly as it is a PHP magic method that
will be implicitly called when executing isset($object->property)
.
Note that if the property is not defined, false will be returned.
public boolean __isset ( $name ) | ||
$name | string |
The property name or the event name |
return | boolean |
Whether the named property is set (not null). |
---|
public function __isset($name)
{
$getter = 'get' . $name;
if (method_exists($this, $getter)) {
return $this->$getter() !== null;
}
return false;
}
Defined in: yii\base\BaseObject::__set()
Sets value of an object property.
Do not call this method directly as it is a PHP magic method that
will be implicitly called when executing $object->property = $value;
.
See also __get().
public void __set ( $name, $value ) | ||
$name | string |
The property name or the event name |
$value | mixed |
The property value |
throws | yii\base\UnknownPropertyException |
if the property is not defined |
---|---|---|
throws | yii\base\InvalidCallException |
if the property is read-only |
public function __set($name, $value)
{
$setter = 'set' . $name;
if (method_exists($this, $setter)) {
$this->$setter($value);
} elseif (method_exists($this, 'get' . $name)) {
throw new InvalidCallException('Setting read-only property: ' . get_class($this) . '::' . $name);
} else {
throw new UnknownPropertyException('Setting unknown property: ' . get_class($this) . '::' . $name);
}
}
Defined in: yii\base\BaseObject::__unset()
Sets an object property to null.
Do not call this method directly as it is a PHP magic method that
will be implicitly called when executing unset($object->property)
.
Note that if the property is not defined, this method will do nothing. If the property is read-only, it will throw an exception.
public void __unset ( $name ) | ||
$name | string |
The property name |
throws | yii\base\InvalidCallException |
if the property is read only. |
---|
public function __unset($name)
{
$setter = 'set' . $name;
if (method_exists($this, $setter)) {
$this->$setter(null);
} elseif (method_exists($this, 'get' . $name)) {
throw new InvalidCallException('Unsetting read-only property: ' . get_class($this) . '::' . $name);
}
}
Binds a column to a PHP variable.
When rows of data are being fetched, the corresponding column value will be set in the variable. Note, the fetch mode must include PDO::FETCH_BOUND.
See also https://www.php.net/manual/en/function.PDOStatement-bindColumn.php.
public void bindColumn ( $column, &$value, $dataType = null ) | ||
$column | integer|string |
Number of the column (1-indexed) or name of the column in the result set. If using the column name, be aware that the name should match the case of the column, as returned by the driver. |
$value | mixed |
Name of the PHP variable to which the column will be bound. |
$dataType | integer|null |
Data type of the parameter |
public function bindColumn($column, &$value, $dataType = null)
{
if ($dataType === null) {
$this->_statement->bindColumn($column, $value);
} else {
$this->_statement->bindColumn($column, $value, $dataType);
}
}
Defined in: yii\base\BaseObject::canGetProperty()
Returns a value indicating whether a property can be read.
A property is readable if:
- the class has a getter method associated with the specified name (in this case, property name is case-insensitive);
- the class has a member variable with the specified name (when
$checkVars
is true);
See also canSetProperty().
public boolean canGetProperty ( $name, $checkVars = true ) | ||
$name | string |
The property name |
$checkVars | boolean |
Whether to treat member variables as properties |
return | boolean |
Whether the property can be read |
---|
public function canGetProperty($name, $checkVars = true)
{
return method_exists($this, 'get' . $name) || $checkVars && property_exists($this, $name);
}
Defined in: yii\base\BaseObject::canSetProperty()
Returns a value indicating whether a property can be set.
A property is writable if:
- the class has a setter method associated with the specified name (in this case, property name is case-insensitive);
- the class has a member variable with the specified name (when
$checkVars
is true);
See also canGetProperty().
public boolean canSetProperty ( $name, $checkVars = true ) | ||
$name | string |
The property name |
$checkVars | boolean |
Whether to treat member variables as properties |
return | boolean |
Whether the property can be written |
---|
public function canSetProperty($name, $checkVars = true)
{
return method_exists($this, 'set' . $name) || $checkVars && property_exists($this, $name);
}
::class
instead.
Defined in: yii\base\BaseObject::className()
Returns the fully qualified name of this class.
public static string className ( ) | ||
return | string |
The fully qualified name of this class. |
---|
public static function className()
{
return get_called_class();
}
Closes the reader.
This frees up the resources allocated for executing this SQL statement. Read attempts after this method call are unpredictable.
public void close ( ) |
public function close()
{
$this->_statement->closeCursor();
$this->_closed = true;
}
Returns the number of rows in the result set.
This method is required by the Countable interface. Note, most DBMS may not give a meaningful count. In this case, use "SELECT COUNT(*) FROM tableName" to obtain the number of rows.
public integer count ( ) | ||
return | integer |
Number of rows contained in the result. |
---|
#[\ReturnTypeWillChange]
public function count()
{
return $this->getRowCount();
}
Returns the current row.
This method is required by the interface Iterator.
public mixed current ( ) | ||
return | mixed |
The current row. |
---|
#[\ReturnTypeWillChange]
public function current()
{
return $this->_row;
}
Returns the number of columns in the result set.
Note, even there's no row in the reader, this still gives correct column number.
public integer getColumnCount ( ) | ||
return | integer |
The number of columns in the result set. |
---|
public function getColumnCount()
{
return $this->_statement->columnCount();
}
Whether the reader is closed or not.
public boolean getIsClosed ( ) | ||
return | boolean |
Whether the reader is closed or not. |
---|
public function getIsClosed()
{
return $this->_closed;
}
Returns the number of rows in the result set.
Note, most DBMS may not give a meaningful count. In this case, use "SELECT COUNT(*) FROM tableName" to obtain the number of rows.
public integer getRowCount ( ) | ||
return | integer |
Number of rows contained in the result. |
---|
public function getRowCount()
{
return $this->_statement->rowCount();
}
Defined in: yii\base\BaseObject::hasMethod()
Returns a value indicating whether a method is defined.
The default implementation is a call to php function method_exists()
.
You may override this method when you implemented the php magic method __call()
.
public boolean hasMethod ( $name ) | ||
$name | string |
The method name |
return | boolean |
Whether the method is defined |
---|
public function hasMethod($name)
{
return method_exists($this, $name);
}
Defined in: yii\base\BaseObject::hasProperty()
Returns a value indicating whether a property is defined.
A property is defined if:
- the class has a getter or setter method associated with the specified name (in this case, property name is case-insensitive);
- the class has a member variable with the specified name (when
$checkVars
is true);
See also:
public boolean hasProperty ( $name, $checkVars = true ) | ||
$name | string |
The property name |
$checkVars | boolean |
Whether to treat member variables as properties |
return | boolean |
Whether the property is defined |
---|
public function hasProperty($name, $checkVars = true)
{
return $this->canGetProperty($name, $checkVars) || $this->canSetProperty($name, false);
}
Defined in: yii\base\BaseObject::init()
Initializes the object.
This method is invoked at the end of the constructor after the object is initialized with the given configuration.
public void init ( ) |
public function init()
{
}
Returns the index of the current row.
This method is required by the interface Iterator.
public integer key ( ) | ||
return | integer |
The index of the current row. |
---|
#[\ReturnTypeWillChange]
public function key()
{
return $this->_index;
}
Moves the internal pointer to the next row.
This method is required by the interface Iterator.
public void next ( ) |
#[\ReturnTypeWillChange]
public function next()
{
$this->_row = $this->_statement->fetch();
$this->_index++;
}
Advances the reader to the next result when reading the results of a batch of statements.
This method is only useful when there are multiple result sets returned by the query. Not all DBMS support this feature.
public boolean nextResult ( ) | ||
return | boolean |
Returns true on success or false on failure. |
---|
public function nextResult()
{
if (($result = $this->_statement->nextRowset()) !== false) {
$this->_index = -1;
}
return $result;
}
Advances the reader to the next row in a result set.
public array read ( ) | ||
return | array |
The current row, false if no more row available |
---|
public function read()
{
return $this->_statement->fetch();
}
Reads the whole result set into an array.
public array readAll ( ) | ||
return | array |
The result set (each array element represents a row of data). An empty array will be returned if the result contains no row. |
---|
public function readAll()
{
return $this->_statement->fetchAll();
}
Returns a single column from the next row of a result set.
public mixed readColumn ( $columnIndex ) | ||
$columnIndex | integer |
Zero-based column index |
return | mixed |
The column of the current row, false if no more rows available |
---|
public function readColumn($columnIndex)
{
return $this->_statement->fetchColumn($columnIndex);
}
Returns an object populated with the next row of data.
public mixed readObject ( $className, $fields ) | ||
$className | string |
Class name of the object to be created and populated |
$fields | array |
Elements of this array are passed to the constructor |
return | mixed |
The populated object, false if no more row of data available |
---|
public function readObject($className, $fields)
{
return $this->_statement->fetchObject($className, $fields);
}
Resets the iterator to the initial state.
This method is required by the interface Iterator.
public void rewind ( ) | ||
throws | yii\base\InvalidCallException |
if this method is invoked twice |
---|
#[\ReturnTypeWillChange]
public function rewind()
{
if ($this->_index < 0) {
$this->_row = $this->_statement->fetch();
$this->_index = 0;
} else {
throw new InvalidCallException('DataReader cannot rewind. It is a forward-only reader.');
}
}
Set the default fetch mode for this statement.
See also https://www.php.net/manual/en/function.PDOStatement-setFetchMode.php.
public void setFetchMode ( $mode ) | ||
$mode | integer |
Fetch mode |
public function setFetchMode($mode)
{
$params = func_get_args();
call_user_func_array([$this->_statement, 'setFetchMode'], $params);
}
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