+### Database username management (for MySQL, PostgreSQL,...) by Chef Vault
+
+- create vault items.
+
+```text
+$ cat ~/sec/tmp/screwdriver_db_username.json
+{"username":"********************************"}
+
+$ cd $CHEF_REPO_PATH
+$ knife vault create screwdriver db_username --json ~/sec/tmp/screwdriver_db_username.json
+```
+
+- grant reference permission to the screwdriver host
+
+```text
+$ knife vault update screwdriver db_username -S 'name:screwdriver-host.example.com'
+```
+
+- modify attributes
+
+```ruby
+override_attributes(
+ 'screwdriver' => {
+ # ...
+ 'db_username_vault_item' => {
+ 'vault' => 'screwdriver',
+ 'name' => 'db_username',
+ 'env_context' => false,
+ 'key' => 'username',
+ },
+ # ...
+ },
+)
+```
+
+### Database password management (for MySQL, PostgreSQL,...) by Chef Vault
+
+- create vault items.
+
+```text
+$ cat ~/sec/tmp/screwdriver_db_password.json
+{"password":"********************************"}
+
+$ cd $CHEF_REPO_PATH
+$ knife vault create screwdriver db_password --json ~/sec/tmp/screwdriver_db_password.json
+```
+
+- grant reference permission to the screwdriver host
+
+```text
+$ knife vault update screwdriver db_password -S 'name:screwdriver-host.example.com'
+```
+
+- modify attributes
+
+```ruby
+override_attributes(
+ 'screwdriver' => {
+ # ...
+ 'db_password_vault_item' => {
+ 'vault' => 'screwdriver',
+ 'name' => 'db_password',
+ 'env_context' => false,
+ 'key' => 'password',
+ },
+ # ...
+ },
+)
+```
+
+### Database root password management (for MySQL, PostgreSQL,...) by Chef Vault
+
+- create vault items.
+
+```text
+$ cat ~/sec/tmp/screwdriver_db_root_password.json
+{"password":"********************************"}
+
+$ cd $CHEF_REPO_PATH
+$ knife vault create screwdriver db_root_password --json ~/sec/tmp/screwdriver_db_root_password.json
+```
+
+- grant reference permission to the screwdriver host
+
+```text
+$ knife vault update screwdriver db_root_password -S 'name:screwdriver-host.example.com'
+```
+
+- modify attributes
+
+```ruby
+override_attributes(
+ 'screwdriver' => {
+ # ...
+ 'db_root_password_vault_item' => {
+ 'vault' => 'screwdriver',
+ 'name' => 'db_root_password',
+ 'env_context' => false,
+ 'key' => 'password',
+ },
+ # ...
+ },
+)
+```
+