add @throws declarations to docs in Connection

In a few cases methods in Connection may throw a DBALException which
isn't declared in the docblock. As the Connection class is heavily
used by third party code, this code runs the risk of ignoring
those exceptions instead of handling them. While it is
technically not required to declare exceptions in PHP, it is highly
recommended, especially in public APIs.

lib/Doctrine/DBAL/Connection.php

@@ -322,6 +322,8 @@ class Connection implements DriverConnection
      * Gets the DatabasePlatform for the connection.
      *
      * @return \Doctrine\DBAL\Platforms\AbstractPlatform
+     *
+     * @throws \Doctrine\DBAL\DBALException
      */
     public function getDatabasePlatform()
     {
@@ -410,6 +412,8 @@ class Connection implements DriverConnection
      * version without having to query it (performance reasons).
      *
      * @return string|null
+     *
+     * @throws \Exception
      */
     private function getDatabasePlatformVersion()
     {
@@ -545,6 +549,8 @@ class Connection implements DriverConnection
      * @param array  $types     The query parameter types.
      *
      * @return array|bool False is returned if no rows are found.
+     *
+     * @throws \Doctrine\DBAL\DBALException
      */
     public function fetchAssoc($statement, array $params = array(), array $types = array())
     {
@@ -576,6 +582,8 @@ class Connection implements DriverConnection
      * @param array  $types      The query parameter types.
      *
      * @return mixed|bool False is returned if no rows are found.
+     *
+     * @throws \Doctrine\DBAL\DBALException
      */
     public function fetchColumn($statement, array $params = array(), $column = 0, array $types = array())
     {
@@ -643,6 +651,7 @@ class Connection implements DriverConnection
      *
      * @return integer The number of affected rows.
      *
+     * @throws \Doctrine\DBAL\DBALException
      * @throws InvalidArgumentException
      */
     public function delete($tableExpression, array $identifier, array $types = array())
@@ -711,6 +720,8 @@ class Connection implements DriverConnection
      * @param array  $types      Types of the merged $data and $identifier arrays in that order.
      *
      * @return integer The number of affected rows.
+     *
+     * @throws \Doctrine\DBAL\DBALException
      */
     public function update($tableExpression, array $data, array $identifier, array $types = array())
     {
@@ -748,6 +759,8 @@ class Connection implements DriverConnection
      * @param array  $types     Types of the inserted data.
      *
      * @return integer The number of affected rows.
+     *
+     * @throws \Doctrine\DBAL\DBALException
      */
     public function insert($tableExpression, array $data, array $types = array())
     {
@@ -1165,7 +1178,8 @@ class Connection implements DriverConnection
      *
      * @return mixed The value returned by $func
      *
-     * @throws \Exception
+     * @throws Exception
+     * @throws Throwable
      */
     public function transactional(Closure $func)
     {