Drupal 8.0.0 beta 12. More info: https://www.drupal.org/node/2514176

core/modules/user/src/UserStorageSchema.php

@@ -0,0 +1,74 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\user\UserStorageSchema.
+ */
+
+namespace Drupal\user;
+
+use Drupal\Core\Entity\ContentEntityTypeInterface;
+use Drupal\Core\Entity\Sql\SqlContentEntityStorageSchema;
+use Drupal\Core\Field\FieldStorageDefinitionInterface;
+
+/**
+ * Defines the user schema handler.
+ */
+class UserStorageSchema extends SqlContentEntityStorageSchema {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getEntitySchema(ContentEntityTypeInterface $entity_type, $reset = FALSE) {
+    $schema = parent::getEntitySchema($entity_type, $reset);
+
+    $schema['users_field_data']['unique keys'] += array(
+      'user__name' => array('name', 'langcode'),
+    );
+
+    return $schema;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function processIdentifierSchema(&$schema, $key) {
+    // The "users" table does not use serial identifiers.
+    if ($key != $this->entityType->getKey('id')) {
+      parent::processIdentifierSchema($schema, $key);
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getSharedTableFieldSchema(FieldStorageDefinitionInterface $storage_definition, $table_name, array $column_mapping) {
+    $schema = parent::getSharedTableFieldSchema($storage_definition, $table_name, $column_mapping);
+    $field_name = $storage_definition->getName();
+
+    if ($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;
+          // Make sure the field is no longer than 191 characters so we can
+          // add a unique constraint in MySQL.
+          $schema['fields'][$field_name]['length'] = USERNAME_MAX_LENGTH;
+          break;
+
+        case 'mail':
+          $this->addSharedTableFieldIndex($storage_definition, $schema);
+          break;
+
+        case 'access':
+        case 'created':
+          $this->addSharedTableFieldIndex($storage_definition, $schema, TRUE);
+          break;
+      }
+    }
+
+    return $schema;
+  }
+
+}