diff -u b/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php b/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php
--- b/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php
+++ b/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php
@@ -2322,6 +2322,8 @@
       // A dedicated table only contain rows for actual field values, and no
       // rows for entities where the field is empty. Thus, we can safely
       // enforce 'not null' on the columns for the field's required properties.
+      // Fields can have dynamic properties, so we need to make sure that the
+      // property is statically defined.
       if (isset($properties[$column_name])) {
         $data_schema['fields'][$real_name]['not null'] = $properties[$column_name]->isRequired();
       }
reverted:
--- b/core/tests/Drupal/KernelTests/Core/Entity/EntityDefinitionUpdateTest.php
+++ a/core/tests/Drupal/KernelTests/Core/Entity/EntityDefinitionUpdateTest.php
@@ -1324,26 +1324,4 @@
     }
   }
 
-  /**
-   * Tests uninstalling map item base field.
-   */
-  public function testUninstallMapItemBaseField() {
-    $definitions['data_map'] = BaseFieldDefinition::create('map')
-      ->setLabel(t('Data'))
-      ->setRequired(TRUE);
-
-    $this->state->set('entity_test_update.additional_base_field_definitions', $definitions);
-
-    $this->entityDefinitionUpdateManager->installFieldStorageDefinition('data_map', 'entity_test_update', 'entity_test', $definitions['data_map']);
-
-    $entity = EntityTestUpdate::create([
-      'data_map' => [
-        'key' => 'value',
-      ],
-    ]);
-    $entity->save();
-
-    $this->entityDefinitionUpdateManager->uninstallFieldStorageDefinition($definitions['data_map']);
-  }
-
 }
only in patch2:
unchanged:
--- /dev/null
+++ b/core/tests/Drupal/KernelTests/Core/Field/MapBaseFieldTest.php
@@ -0,0 +1,65 @@
+<?php
+
+namespace Drupal\KernelTests\Core\Field;
+
+use Drupal\Core\Field\BaseFieldDefinition;
+use Drupal\entity_test_update\Entity\EntityTestUpdate;
+use Drupal\KernelTests\Core\Entity\EntityKernelTestBase;
+
+/**
+ * Tests map base fields.
+ *
+ * @group Field
+ */
+class MapBaseFieldTest extends EntityKernelTestBase {
+
+  /**
+   * The entity definition update manager.
+   *
+   * @var \Drupal\Core\Entity\EntityDefinitionUpdateManagerInterface
+   */
+  protected $entityDefinitionUpdateManager;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['entity_test_update'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    $this->entityDefinitionUpdateManager = $this->container->get('entity.definition_update_manager');
+
+    // Install every entity type's schema that wasn't installed in the parent
+    // method.
+    foreach (array_diff_key($this->entityTypeManager->getDefinitions(), array_flip(['user', 'entity_test'])) as $entity_type_id => $entity_type) {
+      $this->installEntitySchema($entity_type_id);
+    }
+  }
+
+  /**
+   * Tests uninstalling map item base field.
+   */
+  public function testUninstallMapItemBaseField() {
+    $definitions['data_map'] = BaseFieldDefinition::create('map')
+      ->setLabel(t('Data'))
+      ->setRequired(TRUE);
+
+    $this->state->set('entity_test_update.additional_base_field_definitions', $definitions);
+
+    $this->entityDefinitionUpdateManager->installFieldStorageDefinition('data_map', 'entity_test_update', 'entity_test', $definitions['data_map']);
+
+    $entity = EntityTestUpdate::create([
+      'data_map' => [
+        'key' => 'value',
+      ],
+    ]);
+    $entity->save();
+
+    $this->entityDefinitionUpdateManager->uninstallFieldStorageDefinition($definitions['data_map']);
+  }
+
+}