/**
* Parses the provided function call into a database function expression
* @param string $function String of the function expression
* @return boolean|zibo\library\database\manipulation\expression\FunctionExpression false if the
* provided function expression could not be parsed, the function expression object otherwise.
*/
private function parseFunction($function)
{
if (!preg_match(self::REGEX_FUNCTION, $function, $matches)) {
return false;
}
$name = trim($matches[1]);
if (!$name) {
return false;
}
$arguments = $matches[3];
$alias = null;
if (isset($matches[6])) {
$alias = $matches[6];
}
$function = new FunctionExpression($name, $alias);
if (strpos($arguments, 'DISTINCT ') === 0) {
$function->setDistinct(true);
$arguments = substr($arguments, 9);
}
$argumentTokens = $this->fieldTokenizer->tokenize($arguments);
foreach ($argumentTokens as $argument) {
$argument = $this->parseExpression($argument);
$function->addArgument($argument);
}
return $function;
}
/**
* Parses and processes order strings into database order expressions
* @param array $orderBy Array with order strings
* @return array Array with OrderExpression objects
*/
private function parseOrderBy(array $orderBy)
{
$parsedOrderBy = array();
foreach ($orderBy as $index => $order) {
$this->expressionParser->setVariables($order->getVariables());
$tokens = $this->fieldTokenizer->tokenize($order->getExpression());
foreach ($tokens as $token) {
$parsedOrderBy[] = $this->parseOrder($token);
}
}
$this->expressionParser->setVariables(null);
return $parsedOrderBy;
}
/**
* Removes the provided fields from this query.
* @return null
*/
public function removeFields($expression)
{
$this->setModelFields();
$expressions = self::$fieldTokenizer->tokenize($expression);
foreach ($expressions as $expression) {
foreach ($this->fields as $index => $fieldExpression) {
if ($fieldExpression->getExpression() == $expression) {
unset($this->fields[$index]);
return;
}
}
throw new OrmException('Provided expression ' . $expression . ' was not found in this query');
}
}
