Is it possible to validate the data before it is entered into couchbase? I did not find any documentation confirming this. But I believe there must be some way to do it.
You can validate the input by adding another entity "validate_doc_update" to the _design/ document.The validate_doc_update function gets executed for each document you want to create or update. If the validation function raises an exception, the update is denied; when it doesn’t, the updates are accepted. It is optional i.e. if you do not write one, no checking will be done.
More details can be found on http://guide.couchdb.org/draft/validation.html
Couchbase will look at the data to make sure it is in a format it can store, but I doubtt that is what you mean by validation. If by data validation you mean that Couchbase will look at the data coming in and check it for a valid schema or something of that nature than no.