If you're a typical PHP developer, it doesn't take a thorough review of past projects to pick out a telling pattern: In most (if not all) cases, you're probably getting PHP to talk to a database back end for all that dynamic data goodness; in 99 percent of those instances, you're using MySQL. Now, there's nothing wrong with using a relational database.

"I’ve been poking around with CouchDb, like all the cool kids. It’s pretty clever; a database which isn’t relational, where the connection API is REST, and where queries are written in JavaScript and data is returned as JSON..."

Apache CouchDB is a document-oriented database that can be queried and indexed in a MapReduce fashion using JavaScript. CouchDB also offers incremental replication with bi-directional conflict detection and resolution.

"...CouchDB is not a relational database but rather a distributed document database. Instead of inserting a row of column values into a table, you save a document, with any number of named fields and values (now represented as JSON objects) into the database where it exists in a kind of addressable pool.

Cassandra is a distributed database with a BigTable data model running on a Dynamo like infrastructure. It is column-oriented and allows for the storage of relatively structured data. It has a fully decentralized model; every node is identical and there is no single point of failure.

SQL-based relational database management systems (RDBMS) are beginning to be challenged by a new movement of NoSQL databases. Among those NoSQL databases is the open source CouchDB...

Apache CouchDB 1.0.0 users are at risk of potential data loss as a critical bug is found in the NoSQL database

"The CouchDB development team is proud to announce CouchDB version 0.7.0 is now available at http://code.google.com/p/couchdb/downloads/list ..."

A couple weeks ago I wrote about NoSQL and provided a short overview of the landscape of non-relational databases. One that has become increasingly popular is Apache CouchDB, so I’d like to spend a couple weeks digging into it a bit and talking about why it’s so interesting. Before I do, it’s worth noting that Ubuntu 9.10 was just released and uses CouchDB under the hood.