diff --git a/core/lib/Drupal/Core/Entity/FieldableDatabaseStorageController.php b/core/lib/Drupal/Core/Entity/FieldableDatabaseStorageController.php
index 7791b47..afca009 100644
--- a/core/lib/Drupal/Core/Entity/FieldableDatabaseStorageController.php
+++ b/core/lib/Drupal/Core/Entity/FieldableDatabaseStorageController.php
@@ -28,7 +28,7 @@
  * This class can be used as-is by most simple entity types. Entity types
  * requiring special handling can extend the class.
  */
-class FieldableDatabaseStorageController extends FieldableEntityStorageControllerBase implements SchemaStorageControllerInterface {
+class FieldableDatabaseStorageController extends FieldableEntityStorageControllerBase implements SqlStorageControllerInterface {
 
   /**
    * Name of entity's revision database table field, if it supports revisions.
diff --git a/core/lib/Drupal/Core/Entity/Schema/EntitySchemaBuilder.php b/core/lib/Drupal/Core/Entity/Schema/EntitySchemaBuilder.php
index 5d39783..1523d58 100644
--- a/core/lib/Drupal/Core/Entity/Schema/EntitySchemaBuilder.php
+++ b/core/lib/Drupal/Core/Entity/Schema/EntitySchemaBuilder.php
@@ -84,7 +84,8 @@ public function getAllSchema(ContentEntityType $entity_type, array $field_defini
           }
 
           // The entity key fields need to be handled separately.
-          if (FALSE !== $key = array_search($field_name, $entity_keys)) {
+          if (in_array($field_name, $entity_keys)) {
+            $key = array_search($field_name, $entity_keys);
             if ($key !== 'default_language') {
               $this->addFieldSchema($schema[$tables['base_table']], $field_name, $field_definition);
             }
diff --git a/core/lib/Drupal/Core/Entity/SqlStorageControllerInterface.php b/core/lib/Drupal/Core/Entity/SqlStorageControllerInterface.php
index 4a592e7..2e7df52 100644
--- a/core/lib/Drupal/Core/Entity/SqlStorageControllerInterface.php
+++ b/core/lib/Drupal/Core/Entity/SqlStorageControllerInterface.php
@@ -7,7 +7,7 @@
 namespace Drupal\Core\Entity;
 
 /**
- * A common interface for storage controllers that manage a database schema.
+ * A common interface for SQL-based storage controllers.
  */
 interface SqlStorageControllerInterface {
 
diff --git a/core/lib/Drupal/Core/Extension/ModuleHandler.php b/core/lib/Drupal/Core/Extension/ModuleHandler.php
index 44501ee..1bd0116 100644
--- a/core/lib/Drupal/Core/Extension/ModuleHandler.php
+++ b/core/lib/Drupal/Core/Extension/ModuleHandler.php
@@ -10,7 +10,7 @@
 use Drupal\Component\Graph\Graph;
 use Drupal\Core\Entity\ContentEntityType;
 use Drupal\Core\Entity\EntityTypeInterface;
-use Drupal\Core\Entity\SchemaStorageControllerInterface;
+use Drupal\Core\Entity\SqlStorageControllerInterface;
 use Symfony\Component\Yaml\Parser;
 use Drupal\Component\Utility\NestedArray;
 use Drupal\Core\Cache\CacheBackendInterface;
@@ -673,7 +673,7 @@ public function install(array $module_list, $enable_dependencies = TRUE) {
         });
         foreach ($entity_types as $entity_type) {
           $storage_controller = $entity_manager->getStorageController($entity_type->id());
-          if ($storage_controller instanceof SchemaStorageControllerInterface) {
+          if ($storage_controller instanceof SqlStorageControllerInterface) {
             foreach ($storage_controller->getSchema() as $table_name => $table_schema) {
               // @todo Remove this check once all entity types have been converted
               //   to an automatic schema.
@@ -796,7 +796,7 @@ public function uninstall(array $module_list, $uninstall_dependents = TRUE) {
       });
       foreach ($entity_types as $entity_type) {
         $storage_controller = $entity_manager->getStorageController($entity_type->id());
-        if ($storage_controller instanceof SchemaStorageControllerInterface) {
+        if ($storage_controller instanceof SqlStorageControllerInterface) {
           foreach ($storage_controller->getSchema() as $table_name => $table_schema) {
             // @todo Remove this check once all entity types have been converted
             //   to an automatic schema.
diff --git a/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
index 240358b..c5f1388 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
@@ -10,7 +10,7 @@
 use Drupal\Component\Utility\String;
 use Drupal\Core\DependencyInjection\ContainerBuilder;
 use Drupal\Core\DrupalKernel;
-use Drupal\Core\Entity\SchemaStorageControllerInterface;
+use Drupal\Core\Entity\SqlStorageControllerInterface;
 use Drupal\Core\KeyValueStore\KeyValueMemoryFactory;
 use Drupal\Core\Language\Language;
 use Symfony\Component\DependencyInjection\Reference;
@@ -349,7 +349,7 @@ protected function installEntitySchema($entity_type_id) {
     $schema_handler = $this->container->get('database')->schema();
 
     $storage_controller = $entity_manager->getStorageController($entity_type_id);
-    if ($storage_controller instanceof SchemaStorageControllerInterface) {
+    if ($storage_controller instanceof SqlStorageControllerInterface) {
       $schema = $storage_controller->getSchema();
       foreach ($schema as $table_name => $table_schema) {
         $schema_handler->createTable($table_name, $table_schema);