Unlike relational databases, document databases like CouchDB and MongoDB do not directly support entity relationships. This talk will explore patterns of modeling one-to-many and many-to-many entity relationships in a document database. These patterns include using an embedded JSON array, relating documents using identifiers, using a list of keys, and using relationship documents. This talk will explore how these entity relationship patterns equate to how entities are joined in a relational database. We'll take a look at the relevant differences between document databases and relational databases. For example, document databases do not have tables, each document can have its own schema, there is no built-in concept of relationships between documents, views/indexes are queried directly instead of being used to optimize more generalized queries, a column within a result set can contain a mix of logical data types, and there is typically no support for transactions across document boundaries.

He also includes links to two of the tools he mentions in the talk - Doctrine CouchDB and the Doctrine MongoDB ORM.

Lazy loading is the capability of performing a expensive operation on demand, only when it reveals necessary from a client request. [...] In Doctrine 2 I made some architectural choices implementing the proxy approach, which substitute a subclassing object to every association which is not eager-loaded.

There's two main places you can see these differences - in the one/many to one associations dynamic proxies and collection interface.

It's broken us into the key sections - details, a visual tree of the structure, the logic tree and relationships, and, finally the source code. It's a pretty simple process of creating the menu and appending the elements onto it, much like a normal drop down menu. The key is in the set_submenu function, creating a new object for the code to append the submenu elements to. The rest is just simple appends.

They've also included a screenshot to illustrate the end result.

In "Part 1: Definition" we took a look at defining objects and classes in PHP. In "Part 2: Relationships" we looked at linking our objects and classes together. In part 3 I'm going to add to those relationships by looking at visibility, polymorphism and the scope resolution operator.

He starts off with a look at access modifiers (private, public, protected) on both attributes and methods. Next is a look at polymorphism with an example of using a getHTML function in both a base formElement class and the child class of textarea. He then talks about the scope resolution operator (::) and its use in parent/child relationships and in PHP5's scope.

Following on from my posts "Object-Oriented Concepts" and "Object-Oriented Javascript", I'm going to take a look at OOP in PHP.

In "Part 1: Definition" we took a look at defining objects and classes in PHP. In part 2 I'm going to look at the most important part of any object-oriented system - the relationships.

They look at inheritance, association, aggregation, and references. Code examples are sprinkled liberally to help illustrate the points.

The tutorial provides a quick introduction to the functionality of the library - including built-in support for unique keys, table-object generation on the fly, and the benefit of being fully unit tested. Next up, the setup - there's some sample SQL to plug in to follow with the examples and the starting code to get the class included and working. They look at basic crud functionality, with a highlight on selecting, and the relationship handling abilities built-in.