diff --git a/application/MantisBT/Db/DriverAbstract.php b/application/MantisBT/Db/DriverAbstract.php
index 13eea82f87..3e6503b3fe 100644
--- a/application/MantisBT/Db/DriverAbstract.php
+++ b/application/MantisBT/Db/DriverAbstract.php
@@ -19,7 +19,8 @@
 namespace MantisBT\Db;
 
 use MantisBT\Db\PDO\Mysql;
-use MantisBT\Exception\Db;
+use MantisBT\Exception\Database\ParameterCountMismatch;
+use MantisBT\Exception\Database\QueryFailed;
 use MantisBT\Exception\UnspecifiedException;
 
 /**
@@ -147,16 +148,10 @@ protected function queryStart( $sql, array $params=null ) {
 		$this->queries++;
     }
 
-    /**
-     * Called immediately after each db query.
-     * @param mixed db specific result
-     * @return void
-     */
-    public function queryEnd( $result ) {
-        if ( $result !== false ) {
-            return;
-        }
-    }
+	/**
+	 * Called immediately after each db query.
+	 */
+	public function queryEnd() {}
 
     /**
      * Reset internal column details cache
@@ -202,36 +197,35 @@ public function perfGetQueries() {
     }
 
 	/**
-     * Verify sql parameters
-     * @param string $sql query or part of it
-     * @param array $params query parameters
-     * @return array (sql, params, type of params)
-     */
-    public function checkSqlParameters($sql, array $params=null) {
-        $params = (array)$params; // make null array if needed
-
-        // cast booleans to 1/0 int
-        foreach ($params as $key => $value) {
-            $params[$key] = is_bool($value) ? (int)$value : $value;
-        }
+	 * Verify parameters to SQL query string
+	 * @param string $sql SQL query string (or a portion thereof)
+	 * @param array $parameters Query parameters
+	 * @return array An array containing: [0] = SQL query string, [1] = array of parameters
+	 */
+	public function checkSqlParameters($queryString, array $parameters = null) {
+		$expectedParameterCount = substr_count($queryString, '?');
+		$actualParameterCount = 0;
+		if ($parameters !== null) {
+			$actualParameterCount = count($parameters);
+		} else {
+			$parameters = array();
+		}
 
-        $t_count = substr_count($sql, '?');
+		if ($expectedParameterCount !== $actualParameterCount) {
+			throw new ParameterCountMismatch($queryString, $parameters);
+		}
 
-        if (!$t_count) {
-			return array($sql, array() );
-        }
+		if ($actualParameterCount === 0) {
+			return array($queryString, array());
+		} else {
+			// cast booleans to 1/0 int
+			foreach ($parameters as $parameterName => $parameterValue) {
+				$parameters[$parameterName] = is_bool($parameterValue) ? (int)$parameterValue : $parameterValue;
+			}
 
-		if ($t_count == count($params)) {
-			return array($sql, array_values($params));
+			return array($queryString, array_values($parameters));
 		}
-
-		$a = new stdClass;
-		$a->expected = $t_count;
-		$a->actual = count($params);
-		$a->sql = $sql;
-		$a->params = $params;
-		throw new Db( ERROR_DB_QUERY_FAILED, $a );
-    }
+	}
 
 	public function getTableNamePrefix() {
 		return $this->tableNamePrefix;
diff --git a/application/MantisBT/Db/DriverInterface.php b/application/MantisBT/Db/DriverInterface.php
index 6694ff3ee1..cadbd25c6d 100644
--- a/application/MantisBT/Db/DriverInterface.php
+++ b/application/MantisBT/Db/DriverInterface.php
@@ -89,12 +89,10 @@ public function dispose();
      */
     public function queryStart( $sql, array $params=null );
 
-    /**
-     * Called immediately after each db query.
-     * @param mixed db specific result
-     * @return void
-     */
-    public function queryEnd( $result );
+	/**
+	 * Called immediately after each db query.
+	 */
+	public function queryEnd();
 
     /**
      * Returns database server info array
@@ -102,11 +100,6 @@ public function queryEnd( $result );
      */
     public function getServerInfo();
 
-    /**
-     * Returns last error reported by database engine.
-     * @return string error message
-     */
-    public function getLastError();
 
     /**
      * Return tables in database WITHOUT current prefix
diff --git a/application/MantisBT/Db/PDO/Mysql.php b/application/MantisBT/Db/PDO/Mysql.php
index 3e0e755cca..a3daf01fc3 100644
--- a/application/MantisBT/Db/PDO/Mysql.php
+++ b/application/MantisBT/Db/PDO/Mysql.php
@@ -15,12 +15,14 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with MantisBT.  If not, see <http://www.gnu.org/licenses/>.
+
 namespace MantisBT\Db\PDO;
-use MantisBT\Db\DriverInterface;
-use MantisBT\Db\PDO\PDOAbstract;
-use MantisBT\Exception\Db AS DbException;
+
 use \PDO;
 use \PDOException;
+use MantisBT\Db\DriverInterface;
+use MantisBT\Db\PDO\PDOAbstract;
+use MantisBT\Exception\Database\QueryFailed;
 
 /**
  * MYSQL PDO driver class.
@@ -86,9 +88,8 @@ public function databaseExists( $name ) {
 		$sql = "SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMA_NAME = ?";
 		try {
 			$result = $this->execute( $sql, array( $name ) );
-		} catch (PDOException $ex) {
-			throw new DbException(ERROR_DB_QUERY_FAILED, $ex->getMessage());
-			return false;
+		} catch (PDOException $exception) {
+			throw new QueryFailed($exception->getCode(), $exception->getMessage(), $sql);
 		}
 		if ($result) {
 			$value = $result->fetch();
diff --git a/application/MantisBT/Db/PDO/PDOAbstract.php b/application/MantisBT/Db/PDO/PDOAbstract.php
index 302b912cec..95e223796f 100644
--- a/application/MantisBT/Db/PDO/PDOAbstract.php
+++ b/application/MantisBT/Db/PDO/PDOAbstract.php
@@ -18,12 +18,12 @@
 
 namespace MantisBT\Db\PDO;
 
+use \PDO;
+use \PDOException;
 use MantisBT\Db\DriverAbstract;
 use MantisBT\Exception\Database\ConnectionFailed;
 use MantisBT\Exception\Database\DatabaseTypeNotSupported;
-use MantisBT\Exception\Db AS DbException;
-use \PDO;
-use \PDOException;
+use MantisBT\Exception\Database\QueryFailed;
 
 /**
  * Abstract PDO database driver class.
@@ -32,8 +32,15 @@
  */
 abstract class PDOAbstract extends DriverAbstract {
 	protected $pdb;
-	protected $lastError = null;
 
+	/**
+	 * Connect to a database using PDO
+	 * @param string $dsn Database Source Name (DSN) for the connection
+	 * @param string $dbHost Hostname or IP address of the database server
+	 * @param string $dbUser Username
+	 * @param string $dbPass Password
+	 * @param array $dbOptions Optional configuration to pass to PDO
+	 */
 	public function connect($dsn, $dbHost, $dbUser, $dbPass, $dbName, array $dbOptions = null) {
 		$driverStatus = $this->driverInstalled();
 		if ($driverStatus !== true) {
@@ -46,14 +53,13 @@ public function connect($dsn, $dbHost, $dbUser, $dbPass, $dbName, array $dbOptio
 		$this->dbName = $dbName;
 
 		try {
-			$this->pdb = new PDO( $this->getDsn(), $this->dbUser, $this->dbPass, $this->getPdoOptions());
+			$this->pdb = new PDO($this->getDsn(), $this->dbUser, $this->dbPass, $this->getPdoOptions());
 			$this->pdb->setAttribute(PDO::ATTR_CASE, PDO::CASE_LOWER);
 			$this->pdb->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
 			$this->postConnect();
 		} catch (PDOException $exception) {
 			throw new ConnectionFailed($exception->getCode(), $exception->getMessage());
 		}
-		return true;
 	}
 
     /**
@@ -121,43 +127,33 @@ public function getInsertId( $table ) {
 		}
 	}
 
-    /**
-     * Returns last error reported by database engine.
-     * @return string error message
-     */
-    public function getLastError() {
-        return $this->lastError;
-    }
+	/**
+	 * Execute SQL query
+	 * @param string $sql Query string
+	 * @param array $params Array of parameters to insert into query string
+	 * @return PDOStatement Resulting handle for the executed prepared statement
+	 */
+	public function execute($queryString, array $parameters = null) {
+		list( $sql, $params ) = $this->checkSqlParameters($queryString, $parameters);
+		$queryString = $this->remapTableNames($queryString);
 
-    /**
-     * Execute SQL query.
-     * @param string $sql query
-     * @param array $params query parameters
-     * @return bool success
-     */
-    public function execute( $sql, array $params=null ) {
-        list( $sql, $params ) = $this->checkSqlParameters($sql, $params);
-        $sql = $this->remapTableNames($sql);
+		$this->queryStart($queryString, $parameters);
+
+		try {
+			$sth = $this->pdb->prepare($queryString);
+			$sth->execute($parameters);
+		} catch (PDOException $exception) {
+			throw new QueryFailed($exception->getCode(), $exception->getMessage(), $queryString);
+		}
 
-        $result = true;
-        $this->queryStart( $sql, $params );
+		$this->queryEnd();
 
-        try {
-            $sth = $this->pdb->prepare( $sql );
-            $sth->execute( $params );
-        } catch ( PDOException $ex ) {
-            $this->lastError = $ex->getMessage();
-            $result = false;
-        }
-
-        $this->queryEnd( $result );
-        return $result == true ? $sth : false;
-    }
+		return $sth;
+	}
 
     /**
      */
     public function queryStart( $sql, array $params=null ) {
-        $this->lastError = null;
         parent::queryStart( $sql, $params );
     }
 
diff --git a/application/MantisBT/Error.php b/application/MantisBT/Error.php
index 84bf265586..fd4848b7c6 100644
--- a/application/MantisBT/Error.php
+++ b/application/MantisBT/Error.php
@@ -82,7 +82,7 @@ public static function error_handler( $type, $error, $file, $line, $context ) {
         $errorInfo->file = $file;
         $errorInfo->line = $line;
         $errorInfo->context = $context;
-		$errorInfo->trace = debug_backtrace();
+	$errorInfo->trace = debug_backtrace(DEBUG_BACKTRACE_PROVIDE_OBJECT);
 
         self::$allErrors[] = $errorInfo;
 
@@ -135,8 +135,8 @@ public static function shutdown_error_handler() {
         $errorInfo->message = $error['message'];
         $errorInfo->file = $error['file'];
         $errorInfo->line = $error['line'];
-        $errorInfo->trace = debug_backtrace();
-		$errorInfo->context = null;
+        $errorInfo->trace = debug_backtrace(DEBUG_BACKTRACE_PROVIDE_OBJECT);
+	$errorInfo->context = null;
 
         self::$allErrors[] = $errorInfo;
 	}
@@ -295,7 +295,6 @@ public static function error_print_stack_trace( $stack ) {
 		# remove the call to the error handler from the stack trace
 		array_shift( $stack );
 
-
 		foreach( $stack as $frame ) {
 			echo '<tr ', self::error_alternate_class(), '>';
 			echo '<td>', ( isset( $frame['file'] ) ? htmlentities( $frame['file'], ENT_COMPAT, 'UTF-8' ) : '-' ), '</td><td>', ( isset( $frame['line'] ) ? $frame['line'] : '-' ), '</td><td>', ( isset( $frame['class'] ) ? $frame['class'] : '-' ), '</td><td>', ( isset( $frame['type'] ) ? $frame['type'] : '-' ), '</td><td>', ( isset( $frame['function'] ) ? $frame['function'] : '-' ), '</td>';
diff --git a/application/MantisBT/Exception/Database/ParameterCountMismatch.php b/application/MantisBT/Exception/Database/ParameterCountMismatch.php
new file mode 100644
index 0000000000..9a8b0a51d9
--- /dev/null
+++ b/application/MantisBT/Exception/Database/ParameterCountMismatch.php
@@ -0,0 +1,18 @@
+<?php
+namespace MantisBT\Exception\Database;
+use MantisBT\Exception\ExceptionAbstract;
+
+require_api('lang_api.php');
+
+class ParameterCountMismatch extends ExceptionAbstract {
+	public function __construct($queryString, array $parameters) {
+		$expectedParameterCount = substr_count($queryString, '?');
+		$actualParameterCount = count($parameters);
+		/* TODO: add new language string */
+		$errorMessage = lang_get(ERROR_GENERIC, null, false);
+		$errorMessage = sprintf($errorMessage, $expectedParameterCount, $actualParameterCount, $queryString);
+		/* TODO: assign new error code instead of 0 */
+		parent::__construct(0, $errorMessage, null);
+		$this->responseCode = 500;
+	}
+}
diff --git a/application/MantisBT/Exception/Database/QueryFailed.php b/application/MantisBT/Exception/Database/QueryFailed.php
new file mode 100644
index 0000000000..3e49df03c7
--- /dev/null
+++ b/application/MantisBT/Exception/Database/QueryFailed.php
@@ -0,0 +1,14 @@
+<?php
+namespace MantisBT\Exception\Database;
+use MantisBT\Exception\ExceptionAbstract;
+
+require_api('lang_api.php');
+
+class QueryFailed extends ExceptionAbstract {
+	public function __construct($queryErrorCode, $queryErrorDescription, $queryString) {
+		$errorMessage = lang_get(ERROR_DB_QUERY_FAILED, null, false);
+		$errorMessage = sprintf($errorMessage, $queryErrorCode, $queryErrorDescription, $queryString);
+		parent::__construct(ERROR_DB_QUERY_FAILED, $errorMessage, null);
+		$this->responseCode = 500;
+	}
+}
diff --git a/application/MantisBT/Exception/Db.php b/application/MantisBT/Exception/Db.php
deleted file mode 100644
index f3d06098ad..0000000000
--- a/application/MantisBT/Exception/Db.php
+++ /dev/null
@@ -1,17 +0,0 @@
-<?php
-namespace MantisBT\Exception;
-use MantisBT\Exception\ExceptionAbstract;
-
-class Db extends ExceptionAbstract {
-    public function __construct( $code = 0, $parameters, Exception $previous = null ) {
-		/**
-         * if we have some form of database exception, assume that the database don't want to treat
-		 * the database as connected in the exception handler anymore
-         * @todo remove this global
-		 */
-		global $g_db_connected;
-		$g_db_connected = false;
-
-		parent::__construct( $code, $parameters, $previous );
-	}
-}
diff --git a/application/core/database_api.php b/application/core/database_api.php
index bda55c3e72..a997e22008 100644
--- a/application/core/database_api.php
+++ b/application/core/database_api.php
@@ -28,7 +28,6 @@
  *
  * @uses config_api.php
  * @uses constant_inc.php
- * @uses error_api.php
  * @uses logging_api.php
  * @uses utility_api.php
  * @uses adodb/adodb.inc.php
@@ -36,7 +35,6 @@
 
 require_api( 'config_api.php' );
 require_api( 'constant_inc.php' );
-require_api( 'error_api.php' );
 require_api( 'logging_api.php' );
 require_api( 'utility_api.php' );
 
@@ -182,7 +180,7 @@ function db_is_db2() {
  * @param array $p_arr_parms Array of parameters matching $p_query
  * @param int $limit Number of results to return
  * @param int $offset offset query results for paging
- * @return ADORecordSet|bool adodb result set or false if the query failed.
+ * @return mixed Resulting handle for the executed prepared statement
  */
 function db_query_bound( $p_query, $p_arr_parms = null, $p_limit = -1, $p_offset = -1 ) {
 	global $g_queries_array, $g_db, $g_db_log_queries;
@@ -247,13 +245,7 @@ function db_query_bound( $p_query, $p_arr_parms = null, $p_limit = -1, $p_offset
 		array_push( $g_queries_array, array( '', $t_elapsed ) );
 	}
 
-	if( !$t_result ) {
-		db_error( $p_query );
-		trigger_error( ERROR_DB_QUERY_FAILED, ERROR );
-		return false;
-	} else {
-		return $t_result;
-	}
+	return $t_result;
 }
 
 /**
@@ -270,17 +262,15 @@ function db_param() {
  * @return int Record Count
  */
 function db_affected_rows( $result ) {
-	global $g_db;
-
 	return $result->rowCount();
 }
 
 /**
- * Retrieve the next row returned from a specific database query
- * @param bool|ADORecordSet $p_result Database Query Record Set to retrieve next result for.
- * @return array Database result
+ * Retrieve the next row returned from a database query.
+ * @param mixed Result of an executed prepared statement
+ * @return array An array of the next row of the query results
  */
-function db_fetch_array( &$result ) {
+function db_fetch_array( $result ) {
 	return $result->fetch();
 }
 
@@ -382,19 +372,6 @@ function db_field_names( $tableName ) {
 	return is_array( $columns ) ? $columns : array();
 }
 
-/**
- * send both the error number and error message and query (optional) as paramaters for a triggered error
- * @todo Use/Behaviour of this function should be reviewed before 1.2.0 final
- */
-function db_error( $query = null ) {
-	global $g_db;
-	if( null !== $query ) {
-		error_parameters( /* $g_db->ErrorNo(), */ $g_db->getLastError(), $query );
-	} else {
-		error_parameters( /* $g_db->ErrorNo(), */ $g_db->getLastError() );
-	}
-}
-
 /**
  * close the connection.
  * Not really necessary most of the time since a connection is automatically closed when a page finishes loading.