Understanding Form Storage Adapters
Liferay DXP 7.3 and Liferay DXP 7.2 versions that include the fix for LPS-97208 (planned for Liferay DXP 7.2 SP3).
When a user adds a form record, the forms API routes the processing of the request through a storage adapter API. The same is true for the other CRUD operations performed on form entries (read, update, and delete). The default implementation of the storage service is called DefaultDDMStorageAdapter, and as its name implies, it implements the DDMStorageAdapter interface to store form entry data in JSON format.
The Dynamic Data Mapping (DDM) backend can adapt to other storage formats for form records. This makes it easy to serialize form data as XML or YAML (or whatever format you like) instead of the default JSON. You can then choose to store form data anywhere, including the Liferay database.
A newly added storage adapter can only be used with new Forms. All existing Forms continue to use the adapter selected (JSON by default) at the time of their creation, and a different storage adapter cannot be selected.
Saving Form Records
The default JSON implementation responds differently depending on the value of a boolean stored in the save request,