12 calls to db_add_field()

comment_update_8001 in drupal/core/modules/comment/comment.install
Create a UUID column for comments.
hook_update_N in drupal/core/modules/system/system.api.php
Perform a single update.
node_update_8004 in drupal/core/modules/node/node.install
Create a UUID column for nodes.
SchemaTest::assertFieldAdditionRemoval in drupal/core/modules/system/lib/Drupal/system/Tests/Common/SchemaTest.php
Asserts that a given field can be added and removed from a table.
SchemaTest::testSchema in drupal/core/modules/system/lib/Drupal/system/Tests/Common/SchemaTest.php
Tests database interactions.
SchemaTest::testUnsignedColumns in drupal/core/modules/system/lib/Drupal/system/Tests/Common/SchemaTest.php
Tests creating unsigned columns and data integrity thereof.
taxonomy_update_8001 in drupal/core/modules/taxonomy/taxonomy.install
Adds langcode field to {taxonomy_term_data} and {taxonomy_vocabulary}.
taxonomy_update_8002 in drupal/core/modules/taxonomy/taxonomy.install
Create a UUID column for taxonomy terms.
update_prepare_d8_language in drupal/core/includes/update.inc
Prepare Drupal 8 language changes for the bootstrap if needed.
user_update_8001 in drupal/core/modules/user/user.install
Splits {users}.language field to langcode and preferred_langcode.
user_update_8003 in drupal/core/modules/user/user.install
Create a UUID column for users.
user_update_8005 in drupal/core/modules/user/user.install
Creates a preferred_admin_langcode column.