diff --git a/core/lib/Drupal/Core/Database/Database.php b/core/lib/Drupal/Core/Database/Database.php
index d48c6f2..7623ce6 100644
--- a/core/lib/Drupal/Core/Database/Database.php
+++ b/core/lib/Drupal/Core/Database/Database.php
@@ -50,7 +50,7 @@
   /**
    * A processed copy of the database connection information from settings.php.
    *
-   * @var array
+   * @var array[]
    */
   static protected $databaseInfo = array();
 
@@ -78,7 +78,7 @@
    *   '$db_key' => DatabaseLog object.
    * );
    *
-   * @var array
+   * @var \Drupal\Core\Database\Log[]
    */
   static protected $logs = array();
 
@@ -190,6 +190,9 @@
   /**
    * Sets the active connection to the specified key.
    *
+   * @param string $key
+   * Database connection key in settings.php which should be set as active.
+   *
    * @return string|null
    *   The previous database connection key.
    */
@@ -356,6 +359,9 @@
    * @param string $target
    *   The database target to open.
    *
+   * @return \Drupal\Core\Database\Connection
+   *   Connection object to perform database queries.
+   *
    * @throws \Drupal\Core\Database\ConnectionNotDefinedException
    * @throws \Drupal\Core\Database\DriverNotSpecifiedException
    */
diff --git a/core/lib/Drupal/Core/Database/Log.php b/core/lib/Drupal/Core/Database/Log.php
index e45a3be..2094a56 100644
--- a/core/lib/Drupal/Core/Database/Log.php
+++ b/core/lib/Drupal/Core/Database/Log.php
@@ -107,11 +107,11 @@ public function end($logging_key) {
   /**
    * Log a query to all active logging keys.
    *
-   * @param $statement
+   * @param StatementInterface $statement
    *   The prepared statement object to log.
-   * @param $args
+   * @param array args
    *   The arguments passed to the statement object.
-   * @param $time
+   * @param int $time
    *   The time in milliseconds the query took to execute.
    */
   public function log(StatementInterface $statement, $args, $time) {
@@ -137,7 +137,7 @@ public function log(StatementInterface $statement, $args, $time) {
    * the query builders.
    *
    * @link http://www.php.net/debug_backtrace
-   * @return
+   * @return array
    *   This method returns a stack trace entry similar to that generated by
    *   debug_backtrace(). However, it flattens the trace entry and the trace
    *   entry before it so that we get the function and args of the function that