On 9 July 2010 11:53, Alexander Thomas
<[email protected]> wrote:
> Hello everybody,
>
> my name is Alexander Thomas. I'm a freelance web developer from Vienna,
> Austria.
>
> After playing around with CouchDb a bit I finally decided to give it a try in
> a first real life project. So in case my question is trivial, don't hesitate
> to RTFM me and give me a (helpful) pointer.
>
> I have a document type called 'story'. A story can have multiple sections as
> embedded documents, stored in an array.
>
> {
> "_id": "story_14c2f7f84c9701",
> "_rev": "4-abf15eac70a379c9a60b889c9e73357e",
> "type": "story",
> "title": "Untitled",
> "modified": "2010-07-03 20:27:35",
> "sections": [
> {
> "text": "test 1",
> "author_id": id_of_author
> },
> {
> "text": "test 2",
> "author_id": id_of_author
> }
> ]
> }
>
> Each section may have a different author so I store authors in different
> documents to avoid duplicates.
>
>
> Reading the available documentation I was able to connect the story itself to
> an author but what I would like to have is a view, which collects one / all
> stories + the information of the author for each embedded section.
Hi,
CouchDB includes a simple document linking mechanism. You could write
a view that emitted a row for the story, and a row for each section
author with value {"_id": id_of_author}. Then use an include_docs=true
option when querying the view to retrieve the story's doc and all
associated author docs. The view might look something like (untested):
function(doc) {
if (doc.type == 'story') {
emit([doc._id, 'story'], doc._rev);
var authors = {};
for each (var section in doc.sections) {
authors[section.author_id] = true;
}
for (var author in authors) {
emit([doc._id, 'author'], {"_id": author});
}
}
}
However, if you're fetching multiple stories at a time then it's quite
likely that the same author will be retrieved multiple times for
different stories. Also, include_docs=true is not free.
So, if that's not going to work for you then your options are:
1. Include the interesting author attributes in each section.
2. Make two calls to CouchDB - the 1st calls fetches the story or
stories you're interested in; the 2nd call fetches any authors that
appear in the stories you found.
Personally, I'd probably just accept that I need to make two calls.
Hope that helps.
- Matt
