/**
*
* @throws PDOException
*/
public function _query()
{
if ($this->_rowset === false) {
if (self::$_stmt) {
while (self::$_stmt->nextRowset()) {
//如果已经在结果缓存中，则搜寻结果集
$query = array_shift(self::$_fetchingQueue);
$query->_rowset = $query->_fetchAll();
if ($query === $this) {
return;
}
}
self::$_stmt = null;
}
//将当前的语句插到第一个，然后把所有语句一口气打包发送给mysql
$keys = array_keys(self::$_waitingQueue, $this);
if (count($keys)) {
unset(self::$_waitingQueue[$keys[0]]);
}
$sql = $this->_select->assemble();
if (count(self::$_waitingQueue)) {
$sql .= ";\n" . implode(";\n", self::$_waitingQueue);
}
implode(";\n", self::$_waitingQueue);
self::$_stmt = $this->_select->getAdapter()->query($sql);
$this->_rowset = $this->_fetchAll();
self::$_fetchingQueue = self::$_waitingQueue;
self::$_waitingQueue = array();
}
}
/**
* Special handling for PDO query().
* All bind parameter names must begin with ':'
*
* @param string|Select $sql The SQL statement with placeholders.
* @param array $bind An array of data to bind to the placeholders.
* @return PDOStatement
* @throws PDOException.
*/
public function query($sql, $bind = array())
{
if (empty($bind) && $sql instanceof Select) {
$bind = $sql->getBind();
}
if (is_array($bind)) {
foreach ($bind as $name => $value) {
if (!is_int($name) && !preg_match('/^:/', $name)) {
$newName = ":{$name}";
unset($bind[$name]);
$bind[$newName] = $value;
}
}
}
//try {省略throw-catch-rethrow块，直接抛出PDOException
// connect to the database if needed
$this->_connect();
// is the $sql a Select object?
if ($sql instanceof Select) {
if (empty($bind)) {
$bind = $sql->getBind();
}
$sql = $sql->assemble();
}
// make sure $bind to an array;
// don't use (array) typecasting because
// because $bind may be a Expr object
if (!is_array($bind)) {
$bind = array($bind);
}
//将结果缓冲当中的结果集读出来
Statement::flush();
// prepare and execute the statement with profiling
$stmt = $this->prepare($sql);
// 由于取消了Statement，因此将Profiler的控制代码移动到这里
// 由于所处的程序位置，省略了$qp->start(),简化了$qp->bindParams()的相关代码
if ($this->_profiler === false) {
$stmt->execute($bind);
} else {
$q = $this->_profiler->queryStart($sql);
$qp = $this->_profiler->getQueryProfile($q);
if ($qp->hasEnded()) {
$q = $this->_profiler->queryClone($qp);
$qp = $this->_profiler->getQueryProfile($q);
}
$qp->bindParams($bind);
$stmt->execute($bind);
$this->_profiler->queryEnd($q);
}
// return the results embedded in the prepared statement object
$stmt->setFetchMode($this->_fetchMode);
return $stmt;
//} catch (PDOException $e) {
/**
* @see StatementException
*/
//require_once 'Zend/Db/Statement/Exception.php';
//throw new StatementException($e->getMessage(), $e->getCode(), $e);
//}
}
/**
* Performs a validation on the select query before passing back to the parent class.
* Ensures that only columns from the primary DataObject are returned in the result.
*
* @return string|null This object as a SELECT string (or null if a string cannot be produced)
*/
public function assemble()
{
if (count($this->_parts[self::UNION]) == 0) {
$fields = $this->getPart(Select::COLUMNS);
$primary = $this->_info[DataObject::NAME];
$schema = $this->_info[DataObject::SCHEMA];
// If no fields are specified we assume all fields from primary table
if (!count($fields)) {
$this->from($primary, self::SQL_WILDCARD, $schema);
}
}
return parent::assemble();
}
