Issue #3501489 by szato: Error on install - schema error, DB table not created

file_de_duplicator.install

 <?php
 
+/**
+ * @file
+ * Install, update and uninstall functions for the file_de_duplicator module.
+ */
+
 use Drupal\Core\StringTranslation\TranslatableMarkup;
 
 /**
  * Implements hook_schema().
  */
 function file_de_duplicator_schema() {
-  $schema['duplicate_files'] = array(
+  $schema['duplicate_files'] = [
     'description'     => 'Map of duplicate files to originals.',
     'fields'          => [
       'fid'           => [
         'description' => 'File ID of the duplicate',
         'type'        => 'int',
+        'unsigned' => TRUE,
+        'not null' => TRUE,
       ],
       'original_fid'  => [
         'description' => 'File ID of the original',
         'type'        => 'int',
+        'unsigned' => TRUE,
+        'not null' => TRUE,
       ],
       'exact' => [
         'description' => 'Whether exact duplicate',
@@ -32,7 +41,7 @@ function file_de_duplicator_schema() {
       ],
     ],
     'primary key' => ['fid', 'original_fid'],
-  );
+  ];
 
   return $schema;
 }