diff --git a/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/StringItemBase.php b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/StringItemBase.php
index 4772983..11ccec6 100644
--- a/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/StringItemBase.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/StringItemBase.php
@@ -40,4 +40,11 @@ public static function propertyDefinitions(FieldStorageDefinitionInterface $fiel
     return $properties;
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function isEmpty() {
+    return $this->value === NULL || $this->value === '';
+  }
+
 }
diff --git a/core/modules/user/src/Entity/User.php b/core/modules/user/src/Entity/User.php
index 1a78c98..1ade014 100644
--- a/core/modules/user/src/Entity/User.php
+++ b/core/modules/user/src/Entity/User.php
@@ -498,6 +498,7 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
     $fields['name'] = BaseFieldDefinition::create('string')
       ->setLabel(t('Name'))
       ->setDescription(t('The name of this user.'))
+      ->setRequired(TRUE)
       ->setDefaultValue('')
       ->setConstraints(array(
         // No Length constraint here because the UserName constraint also covers
diff --git a/core/modules/user/src/UserStorageSchema.php b/core/modules/user/src/UserStorageSchema.php
index 447469d..3fbbbf9 100644
--- a/core/modules/user/src/UserStorageSchema.php
+++ b/core/modules/user/src/UserStorageSchema.php
@@ -48,12 +48,6 @@ protected function getSharedTableFieldSchema(FieldStorageDefinitionInterface $st
 
     if ($table_name == 'users_field_data') {
       switch ($field_name) {
-        case 'name':
-          // Improves the performance of the user__name index defined
-          // in getEntitySchema().
-          $schema['fields'][$field_name]['not null'] = TRUE;
-          break;
-
         case 'mail':
           $this->addSharedTableFieldIndex($storage_definition, $schema);
           break;
diff --git a/core/modules/user/user.install b/core/modules/user/user.install
index 7b3c3d3..9335cfb 100644
--- a/core/modules/user/user.install
+++ b/core/modules/user/user.install
@@ -70,6 +70,7 @@ function user_install() {
     ->create(array(
       'uid' => 0,
       'status' => 0,
+      'name' => 'Anonymous'
     ))
     ->save();