diff --git a/core/modules/block/block.install b/core/modules/block/block.install
index 8fcecbe..515db48 100644
--- a/core/modules/block/block.install
+++ b/core/modules/block/block.install
@@ -141,7 +141,6 @@ function block_schema() {
     'fields' => array(
       'bid' => array(
         'type' => 'serial',
-        'unsigned' => TRUE,
         'not null' => TRUE,
         'description' => "The block's {block}.bid.",
       ),
diff --git a/core/modules/comment/comment.install b/core/modules/comment/comment.install
index 4b3c9fc..81d63a2 100644
--- a/core/modules/comment/comment.install
+++ b/core/modules/comment/comment.install
@@ -99,12 +99,14 @@ function comment_schema() {
       ),
       'nid' => array(
         'type' => 'int',
+        'unsigned' => TRUE,
         'not null' => TRUE,
         'default' => 0,
         'description' => 'The {node}.nid to which this comment is a reply.',
       ),
       'uid' => array(
         'type' => 'int',
+        'unsigned' => TRUE,
         'not null' => TRUE,
         'default' => 0,
         'description' => 'The {users}.uid who authored the comment. If set to 0, this comment was created by an anonymous user.',
@@ -225,6 +227,7 @@ function comment_schema() {
       ),
       'last_comment_uid' => array(
         'type' => 'int',
+        'unsigned' => TRUE,
         'not null' => TRUE,
         'default' => 0,
         'description' => 'The user ID of the latest author to post a comment on this node, from {comment}.uid.',
diff --git a/core/modules/dblog/dblog.install b/core/modules/dblog/dblog.install
index 23f85ba..0caa53a 100644
--- a/core/modules/dblog/dblog.install
+++ b/core/modules/dblog/dblog.install
@@ -19,6 +19,7 @@ function dblog_schema() {
       ),
       'uid' => array(
         'type' => 'int',
+        'unsigned' => TRUE,
         'not null' => TRUE,
         'default' => 0,
         'description' => 'The {users}.uid of the user who triggered the event.',
diff --git a/core/modules/node/node.install b/core/modules/node/node.install
index 7382320..bc293c7 100644
--- a/core/modules/node/node.install
+++ b/core/modules/node/node.install
@@ -403,12 +403,14 @@ function node_schema() {
       'uid' => array(
         'description' => 'The {users}.uid that read the {node} nid.',
         'type' => 'int',
+        'unsigned' => TRUE,
         'not null' => TRUE,
         'default' => 0,
       ),
       'nid' => array(
         'description' => 'The {node}.nid that was read.',
         'type' => 'int',
+        'unsigned' => TRUE,
         'not null' => TRUE,
         'default' => 0,
       ),
diff --git a/core/modules/user/user.install b/core/modules/user/user.install
index 5ec57da..a6140d7 100644
--- a/core/modules/user/user.install
+++ b/core/modules/user/user.install
@@ -20,6 +20,7 @@ function user_schema() {
       ),
       'uid' => array(
         'type' => 'int',
+        'unsigned' => TRUE,
         'not null' => TRUE,
         'default' => 0,
         'description' => "User's {users}.uid.",