diff --git a/common/framework/helpers/dbhelper.php b/common/framework/helpers/dbhelper.php
index 72c26702f..100f9e701 100644
--- a/common/framework/helpers/dbhelper.php
+++ b/common/framework/helpers/dbhelper.php
@@ -8,6 +8,9 @@ use Rhymix\Framework\Exceptions\DBError;
 
 /**
  * DB helper class.
+ * 
+ * We use instances of this class instead of raw PDO in order to provide
+ * better logging and error handling while keeping backward compatibility.
  */
 class DBHelper extends \PDO
 {
@@ -38,23 +41,32 @@ class DBHelper extends \PDO
 		
 		try
 		{
-			if ($driver_options)
-			{
-				$stmt = parent::prepare($statement, $driver_options);
-			}
-			else
-			{
-				$stmt = parent::prepare($statement);
-			}
+			/**
+			 * $stmt will be an instance of DBStmtHelper.
+			 * This allows it to track the parent database's type
+			 * and send query logs to the appropriate place.
+			 */
+			$stmt = $driver_options ? parent::prepare($statement, $driver_options) : parent::prepare($statement);
 			$stmt->setFetchMode(\PDO::FETCH_OBJ);
 			$stmt->setType($this->_type);
+			$db_class->clearError();
 		}
 		catch (\PDOException $e)
 		{
+			/**
+			 * We only measure the time when the prepared statement fails.
+			 * If the statement is successfully prepared, time will be measured
+			 * when the statement is executed in DBStmtHelper.
+			 */
 			$elapsed_time = microtime(true) - $start_time;
 			$db_class->addElapsedTime($elapsed_time);
 			$db_class->setError(-1, $e->getMessage());
 			Debug::addQuery($db_class->getQueryLog($statement, $elapsed_time));
+			
+			/**
+			 * This is a new feature in Rhymix 2.0 so we don't have to mess
+			 * with status objects. We just throw an exception. Catch it!
+			 */
 			throw new DBError($e->getMessage(), 0, $e);
 		}
 		
@@ -64,6 +76,10 @@ class DBHelper extends \PDO
 	/**
 	 * Execute a query.
 	 * 
+	 * This method accepts additional parameters, but they are not for creating
+	 * prepared statements. They exist because PDO's own query() method accepts
+	 * various kinds of additional parameters, and we don't want to touch them.
+	 * 
 	 * @param string $statement
 	 * @return PDOStatement|DBStmtHelper
 	 */
@@ -76,6 +92,11 @@ class DBHelper extends \PDO
 		
 		try
 		{
+			/**
+			 * $stmt will be an instance of DBStmtHelper.
+			 * This allows it to track the parent database's type
+			 * and send query logs to the appropriate place.
+			 */
 			$stmt = parent::query($statement, ...$args);
 			$stmt->setFetchMode(\PDO::FETCH_OBJ);
 			$stmt->setType($this->_type);
@@ -85,10 +106,12 @@ class DBHelper extends \PDO
 		{
 			$db_class->setError(-1, $e->getMessage());
 		}
-		
-		$elapsed_time = microtime(true) - $start_time;
-		$db_class->addElapsedTime($elapsed_time);
-		Debug::addQuery($db_class->getQueryLog($statement, $elapsed_time));
+		finally
+		{
+			$elapsed_time = microtime(true) - $start_time;
+			$db_class->addElapsedTime($elapsed_time);
+			Debug::addQuery($db_class->getQueryLog($statement, $elapsed_time));
+		}
 		
 		return $stmt;
 	}
@@ -113,10 +136,12 @@ class DBHelper extends \PDO
 		{
 			$db_class->setError(-1, $e->getMessage());
 		}
-		
-		$elapsed_time = microtime(true) - $start_time;
-		$db_class->addElapsedTime($elapsed_time);
-		Debug::addQuery($db_class->getQueryLog($query, $elapsed_time));
+		finally
+		{
+			$elapsed_time = microtime(true) - $start_time;
+			$db_class->addElapsedTime($elapsed_time);
+			Debug::addQuery($db_class->getQueryLog($query, $elapsed_time));
+		}
 		
 		return $result;
 	}
diff --git a/common/framework/helpers/dbstmthelper.php b/common/framework/helpers/dbstmthelper.php
index 7496e8cb2..97adfccd0 100644
--- a/common/framework/helpers/dbstmthelper.php
+++ b/common/framework/helpers/dbstmthelper.php
@@ -8,6 +8,10 @@ use Rhymix\Framework\Exceptions\DBError;
 
 /**
  * DB Statement helper class.
+ * 
+ * We use instances of this class instead of raw PDOStatement in order to log
+ * individual execute() calls of prepared statements. This is controlled by
+ * the PDO::ATTR_STATEMENT_CLASS attribute set in the DB class.
  */
 class DBStmtHelper extends \PDOStatement
 {
@@ -27,6 +31,10 @@ class DBStmtHelper extends \PDOStatement
 	/**
 	 * Execute a prepared statement.
 	 * 
+	 * We don't set a type for $input_parameters because the original
+	 * PDOStatement class accepts both arrays and null. Actually, the null
+	 * value must be omitted altogether or it will throw an error.
+	 * 
 	 * @param array $input_parameters
 	 * @return bool
 	 */
@@ -39,19 +47,17 @@ class DBStmtHelper extends \PDOStatement
 		{
 			$result = parent::execute($input_parameters);
 			$db_class->clearError();
-			
-			$elapsed_time = microtime(true) - $start_time;
-			$db_class->addElapsedTime($elapsed_time);
-			Debug::addQuery($db_class->getQueryLog($this->queryString, $elapsed_time));
 		}
 		catch (\PDOException $e)
 		{
 			$db_class->setError(-1, $e->getMessage());
-			
+			throw new DBError($e->getMessage(), 0, $e);
+		}
+		finally
+		{
 			$elapsed_time = microtime(true) - $start_time;
 			$db_class->addElapsedTime($elapsed_time);
 			Debug::addQuery($db_class->getQueryLog($this->queryString, $elapsed_time));
-			throw new DBError($e->getMessage(), 0, $e);
 		}
 		
 		return $result;