Blog

GETting Documents From CouchDB

July 2, 2009

To start off, here are the links to my previous posts about CouchDB:

  1. Relaxing on the Couch(DB)
  2. Installing the Couch(DB)
  3. PUTting the Couch(DB) in Your Living Room

In my latest post, I explained how easy it is to create and manage documents in CouchDB. Today, I want to talk about how to retrieve a document from CouchDB.

In order to retrieve a document from CouchDB, we make use of the HTTP GET operation (duh). Using the GET method for retrieving a document takes the following general form:

http://myhost:5984/my_database/my_id

Its as simple as that. So, for example, sending the following request:

makes CouchDB return the following response:

As already mentioned, CouchDB provides MVCC (multi-version concurrency control) for the documents it stores. Using the GET operation makes it possible to take advantage of this built-in feature. Notice that the first digit of the revision number in the example above indicates that this is the second version of the document we retrieved. This means that CouchDB possibly has an earlier version of the document. In order to find out what revisions are available, we can issue the following request:

CouchDB returns the current revision of the document as before, but now with an additional field named _revisions:

In order to retrieve the first revision of our document, we can send the following request to retrieve it:

As expected, CouchDB now returns the first revision of the document:

GET /documentstore/96f49e5a-6b5b-47ed-9234-9a98d600013e

It seems that for the second revision of the document, we have added an extra tag. Having this kind of automatic versioning for your data is a really nice feature in my book.

For my next post, I will talk about how to delete a document from CouchDB..

Till next time

Profile picture of Jan Van Ryswyck

Jan Van Ryswyck

Thank you for visiting my blog. I’m a professional software developer since Y2K. A blogger since Y2K+5. Curator of the Awesome Talks list. Past organizer of the European Virtual ALT.NET meetings. Thinking and learning about all kinds of technologies since forever.

Comments

About

Thank you for visiting my website. I’m a professional software developer since Y2K. A blogger since Y2K+5. Curator of the Awesome Talks list. Past organizer of the European Virtual ALT.NET meetings. Thinking and learning about all kinds of technologies since forever.

Contact information

(+32) 496 38 00 82

infonull@nullprincipal-itnull.be