diff --git a/core/modules/ban/ban.install b/core/modules/ban/ban.install
index 7a5494f..4ff4a54 100644
--- a/core/modules/ban/ban.install
+++ b/core/modules/ban/ban.install
@@ -9,6 +9,14 @@
  * Implements hook_schema().
  */
 function ban_schema() {
+  $schema = ban_schema_0();
+  return $schema;
+}
+
+/**
+ * Implements hook_schema_0().
+ */
+function ban_schema_0() {
   $schema['ban_ip'] = array(
     'description' => 'Stores banned IP addresses.',
     'fields' => array(
diff --git a/core/modules/block/custom_block/custom_block.install b/core/modules/block/custom_block/custom_block.install
index 0e87811..fac5a48 100644
--- a/core/modules/block/custom_block/custom_block.install
+++ b/core/modules/block/custom_block/custom_block.install
@@ -9,104 +9,7 @@
  * Implements hook_schema().
  */
 function custom_block_schema() {
-  $schema = array();
-  $schema['custom_block'] = array(
-    'description' => 'Stores contents of custom-made blocks.',
-    'fields' => array(
-      'id' => array(
-        'type' => 'serial',
-        'unsigned' => TRUE,
-        'not null' => TRUE,
-        'description' => "The block's {custom_block}.id.",
-      ),
-      'uuid' => array(
-        'description' => 'Unique Key: Universally unique identifier for this entity.',
-        'type' => 'varchar',
-        'length' => 128,
-        'not null' => FALSE,
-      ),
-      'info' => array(
-        'type' => 'varchar',
-        'length' => 128,
-        'not null' => TRUE,
-        'default' => '',
-        'description' => 'Block description.',
-      ),
-      // Defaults to NULL in order to avoid a brief period of potential
-      // deadlocks on the index.
-      'revision_id' => array(
-        'description' => 'The current {block_custom_revision}.revision_id version identifier.',
-        'type' => 'int',
-        'unsigned' => TRUE,
-        'not null' => FALSE,
-        'default' => NULL,
-      ),
-      'type' => array(
-        'description' => 'The type of this custom block.',
-        'type' => 'varchar',
-        'length' => 32,
-        'not null' => TRUE,
-        'default' => '',
-      ),
-      'langcode' => array(
-        'description' => 'The {language}.langcode of this node.',
-        'type' => 'varchar',
-        'length' => 12,
-        'not null' => TRUE,
-        'default' => '',
-      ),
-    ),
-    'primary key' => array('id'),
-    'indexes' => array(
-      'block_custom_type'   => array(array('type', 4)),
-    ),
-    'unique keys' => array(
-      'revision_id' => array('revision_id'),
-      'uuid' => array('uuid'),
-      'info' => array('info'),
-    ),
-    'foreign keys' => array(
-      'custom_block_revision' => array(
-        'table' => 'custom_block_revision',
-        'columns' => array('revision_id' => 'revision_id'),
-      ),
-    ),
-  );
-
-  $schema['custom_block_revision'] = array(
-    'description' => 'Stores contents of custom-made blocks.',
-    'fields' => array(
-      'id' => array(
-        'type' => 'int',
-        'unsigned' => TRUE,
-        'not null' => TRUE,
-        'default' => 0,
-        'description' => "The block's {custom_block}.id.",
-      ),
-      // Defaults to NULL in order to avoid a brief period of potential
-      // deadlocks on the index.
-      'revision_id' => array(
-        'description' => 'The current version identifier.',
-        'type' => 'serial',
-        'unsigned' => TRUE,
-        'not null' => TRUE,
-      ),
-      'log' => array(
-        'description' => 'The log entry explaining the changes in this version.',
-        'type' => 'text',
-        'not null' => TRUE,
-        'size' => 'big',
-      ),
-      'info' => array(
-        'type' => 'varchar',
-        'length' => 128,
-        'not null' => TRUE,
-        'default' => '',
-        'description' => 'Block description.',
-      ),
-    ),
-    'primary key' => array('revision_id'),
-  );
+  $schema = custom_block_schema_0();
   return $schema;
 }
 
diff --git a/core/modules/book/book.install b/core/modules/book/book.install
index 786a1cf..a4fc8e1 100644
--- a/core/modules/book/book.install
+++ b/core/modules/book/book.install
@@ -20,6 +20,14 @@ function book_uninstall() {
  * Implements hook_schema().
  */
 function book_schema() {
+  $schema = book_schema_0();
+  return $schema;
+}
+
+/**
+ * Implements hook_schema_0().
+ */
+function book_schema_0() {
   $schema['book'] = array(
   'description' => 'Stores book outline information. Uniquely connects each node in the outline to a link in {menu_links}',
     'fields' => array(
diff --git a/core/modules/content_translation/content_translation.install b/core/modules/content_translation/content_translation.install
index bd817bc..9dee487 100644
--- a/core/modules/content_translation/content_translation.install
+++ b/core/modules/content_translation/content_translation.install
@@ -11,6 +11,14 @@
  * Implements hook_schema().
  */
 function content_translation_schema() {
+  $schema = content_translation_schema_0();
+  return $schema;
+}
+
+/**
+ * Implements hook_schema_0().
+ */
+function content_translation_schema_0() {
   $schema['content_translation'] = array(
     'description' => 'Table to track content translations',
     'fields' => array(
diff --git a/core/modules/forum/forum.install b/core/modules/forum/forum.install
index 60efc30..c502201 100644
--- a/core/modules/forum/forum.install
+++ b/core/modules/forum/forum.install
@@ -131,6 +131,14 @@ function forum_uninstall() {
  * Implements hook_schema().
  */
 function forum_schema() {
+  $schema = forum_schema_0();
+  return $schema;
+}
+
+/**
+ * Implements hook_schema_0().
+ */
+function forum_schema_0() {
   $schema['forum'] = array(
     'description' => 'Stores the relationship of nodes to forum terms.',
     'fields' => array(
diff --git a/core/modules/history/history.install b/core/modules/history/history.install
index dcfd871..416d1e6 100644
--- a/core/modules/history/history.install
+++ b/core/modules/history/history.install
@@ -9,6 +9,14 @@
  * Implements hook_schema().
  */
 function history_schema() {
+  $schema = history_schema_0();
+  return $schema;
+}
+
+/**
+ * Implements hook_schema_0().
+ */
+function history_schema_0() {
   $schema['history'] = array(
     'description' => 'A record of which {users} have read which {node}s.',
     'fields' => array(
diff --git a/core/modules/menu_link/menu_link.install b/core/modules/menu_link/menu_link.install
index 976653f..26a7ddc 100644
--- a/core/modules/menu_link/menu_link.install
+++ b/core/modules/menu_link/menu_link.install
@@ -9,6 +9,14 @@
  * Implements hook_schema().
  */
 function menu_link_schema() {
+  $schema = menu_link_schema_0();
+  return $schema;
+}
+
+/**
+ * Implements hook_schema_0().
+ */
+function menu_link_schema_0() {
   $schema['menu_links'] = array(
     'description' => 'Contains the individual links within a menu.',
     'fields' => array(
diff --git a/core/modules/simpletest/simpletest.install b/core/modules/simpletest/simpletest.install
index 020b3cd..ec926bf 100644
--- a/core/modules/simpletest/simpletest.install
+++ b/core/modules/simpletest/simpletest.install
@@ -74,6 +74,14 @@ function simpletest_requirements($phase) {
  * Implements hook_schema().
  */
 function simpletest_schema() {
+  $schema = simpletest_schema_0();
+  return $schema;
+}
+
+/**
+ * Implements hook_schema_0().
+ */
+function simpletest_schema_0() {
   $schema['simpletest'] = array(
     'description' => 'Stores simpletest messages',
     'fields' => array(