CouchDB is a prominent representative of the NoSQL movement. Using its integrated web server and eventual consistent replication you can not only distribute data, but also full application code. This even works for clients which are not always connected to the internet, like e.g. mobile devices. This session gives you an insight Couch apps, their beauty and pitfalls.

You can either listen via the in-page player, by downloading the mp3 or by subscribing to their feed. You can find his slides over on talks.qafoo.com.

The Data Mapper pattern is a mechanism for persistence where the application model and the data source have no dependencies between each other. [...] But everytime we talk about the Data Mapper pattern, we assume there is a relational database on the other side of the persistence boundary. We always save objects; we always map them to MySQL or Postgres tables; but it's not mandatory.

He talks about two projects, MongoDb_ODM and CouchDb_ODM, that the Doctrine project is working on to help make working with document-driven databases as simple as the usual ORMs. He includes a brief code snippet showing how the feature will work (hint: a namespace of Document instead of Entity). He lists some of the features - including the usual ORM capabilities, support for collections, cascade of persistence - and where you can get the latest code for it (from github and PEAR

Thanks to a comment in my last post (many thanks Benjamin) I've discovered that it's possible to create a stream wrapper in PHP (I thought it was only available with a C extension). It's pretty straightforward to create the wrapper. Of course it's only an approach. We can create more functionality to our stram wrapper but at least this example meets my needs.

His wrapper uses a client from his Nov framework to open the stream to the given path and gives read and write methods to work with the data inside the database. Code for the wrapper class is included as well as a bit of example code showing how it can be used with the custom stream protocol. You can find the complete code here.

There has been a lot of buzz lately about the NoSQL movement in general and CouchDB in particular. For people who are used to relational databases, a lot of CouchDB's limitations look like severe disadvantages; these constraints however can also be great opportunities. This talk will give an overview of CouchDB and then focus on embracing the system's constraints to build better products.

You can either listen in-page or download the mp3 to get this latest episode. If you'd like to follow along with his slides, you can find them on SlideShare.

I will not detail the installation of the CouchDB server, the wiki got enough details. For the rest of this article I will assume that we have a running CouchDB server waiting for our queries on couch.example.com on port 5984 (the default CouchDB port). Setting up PHP on Couch is not really complicated : just download it on github.com, extract the archive : the interesting bits are in the lib folder.

He starts with some of the key terms you'll need on the CouchDb side (like JSON, documents, _id and _rev) followed by the interaction between PHP and the database - creating a database, storing a document, using the document object mapper and working with views.

I'm still working in my filesystem with CouchDb. After creating a library to enable working with PHP and CouchDB (see the post here), and after using Monkey Patching to override standard PHP's filesystem functions. I've created another solution now. Thanks to a comment in my last post (many thanks Benjamin) I've discovered that it's possible to create a stream wrapper in PHP (I thought it was only available with a C extension).

He includes the code for the stream connection wrapper, a pretty simple script that parses the string it's given and opens a read/write stream to the source. There's also a "url_stat" method that will return to you the size of the stream in bytes. Then you just register the wrapper and go about your normal file system calls to use the CouchDb directly.

Since PHP5.3 a new design pattern is available for us: Monkey Patching. With this pattern we can override PHP's core functions with a home-made functions in a different namespace (another example here). That's means if I have fopen function in the above example, PHP uses the filesystem function "fopen" but if we set a namespace in our example, PHP will search first the function within the current namespace.

By defining the new interface inside of a namespace (with functions to override the default PHP file handlers) you can have the rest of the code call the same functions (fopen, fread, etc) but they'll do different things. In this case it handles them as push and pull to the CouchDb instead of the normal filesystem. You can grab the source for this example here.

One of the problems I need to solve in my clustered PHP applications is where to store files. When I say files I'm not speaking about source code. I'm speaking about additional data files, such as download-able pdfs, logs, etc. Those files must be on every node of the cluster. [...] CouchDb has two great features to meet or requirements with this problem. It allows us to store files as attachments and it also allows to perform a great and very easy multi-master replica system.

He shows how use two libraries he's created to connect to the CouchDB instance and, based on this structure, be able to insert the content - a text file in this case - pull it back out, get the meta data about it and even move it to another location in the structure.

I come from relational database world. NoSQL is new for me. Maybe I'm wrong but I want to use INSERT, UPDATE, DELETE and SELECT statements in CouchDB in the same way I use them in Relational database. The class is focused in the HTTP Document API. There is a great tutorial here that explains the API. Now I'll show the interface I've made to perform the statements with CouchDB.

There's examples of both simple and more complex selects, updates and deletes as well as the handling of exceptions via two types he's included support for - NoDataFound and DupValOnIndex.

2010 is the year of the document database. While momentum has been steadily building over the last seven years or so, there are now a wide variety of stable document databases -- from cloud-based ones from Amazon and Google, to a wide variety of Open Source tools, most notably CouchDB and MongoDB. So what is MongoDB? Here are five things every PHP developer should know about it.

He points out a few things - that MongoDB is a stand-alone server, that it's schemaless, you won't need to learn another query language to use it and that PHP and MongoDB play very well together (thanks to the Mongo PECL package already released).