Validate functions are used in CouchDB to validate changes on an old document or the insertion of a new document. In this sense, they provide the security for the system, allowing generally all users to read and only users with particular rights to write or update documents.
See the child pages to see the particular validation functions used in the nEDM Interface. Note that, during insertion or update of a document, all validation functions must return successfully. As a performance consideration, it's important to note that the validation functions are run over all documents as they are posted/updated. For this reason, the validate functions should be kept as slim and quick as possible.