On Nov 5, 2012, at 12:17 PM, Kevin Burton <[email protected]> wrote:
> When I create a new document both the id and rev will be null. So in order to
> determine if the create is a duplicate another field must be involved.
Gotcha. In general, if you have an attribute of a document that must be unique
within the database, it’s a good idea to use that attribute (or a
transformed/canonicalized version of it) as the document ID. That way the
database itself can enforce the uniqueness. Otherwise you can end up in
situations where there are multiple documents with that same attribute value,
if your app supports multiple clients or does replication.
> For example say my document had a field 'title' I could construct a view to
> return all documents that have a given 'title'. The reason that I brought
> this up in this context is that if I could check to see if there were any
> documents that had a particular title then I would be closer to finding out
> if the document had already been inserted in the db.
That’s very easy to do. In generic CouchDB terms (I don’t know DreamSeat or
.NET), you would
* Create a design document containing a view with a map function:
function(doc) {if (doc.title) emit(doc.title, null);}
* Query the view for a particular title by setting the startkey and endkey
parameters to the title. You’ll get back a list of the document(s), if any,
with that title.
* If you get back zero rows from the query, create a new document.
—Jens
