/**
* Builds a sql query with the specified connection
*
* @param SQLExpression $query The expression object to build from
* @param array $parameters Out parameter for the resulting query parameters
* @return string The resulting SQL as a string
*/
public function buildSQL(SQLExpression $query, &$parameters)
{
$sql = null;
$parameters = array();
// Ignore null queries
if ($query->isEmpty()) {
return null;
}
if ($query instanceof SQLSelect) {
$sql = $this->buildSelectQuery($query, $parameters);
} elseif ($query instanceof SQLDelete) {
$sql = $this->buildDeleteQuery($query, $parameters);
} elseif ($query instanceof SQLInsert) {
$sql = $this->buildInsertQuery($query, $parameters);
} elseif ($query instanceof SQLUpdate) {
$sql = $this->buildUpdateQuery($query, $parameters);
} else {
user_error("Not implemented: query generation for type " . $query->getType());
}
return $sql;
}
/**
* Delete this object from the database by specified criteria
*
* @param rdbms.SQLExpression criteria
* @return int number of affected rows
* @throws rdbms.SQLException in case an error occurs
*/
public function doDelete(SQLExpression $criteria)
{
$db = $this->getConnection();
// Send it
return $db->delete('from %c%c', $this->table, $criteria->toSQL($db, $this));
}
/**
* Returns the WHERE clauses ready for inserting into a query.
*
* @param SQLExpression $query The expression object to build from
* @param array $parameters Out parameter for the resulting query parameters
* @return string Completed where condition
*/
public function buildWhereFragment(SQLExpression $query, array &$parameters)
{
// Get parameterised elements
$where = $query->getWhereParameterised($whereParameters);
if (empty($where)) {
return '';
}
// Join conditions
$connective = $query->getConnective();
$parameters = array_merge($parameters, $whereParameters);
$nl = $this->getSeparator();
return "{$nl}WHERE (" . implode("){$nl}{$connective} (", $where) . ")";
}