Tangram is an object-relational mapper: it makes objects persist in conventional relational databases, in effect letting you use RDBMSes as if they were object databases.

Tangram supports inheritance (including multiple inheritance), polymorphism, object identity, relationships (including collections), load-on-demand, etc. It also gives access to the powerful query facilities found in RDBMSes via an intuitive object syntax.

In my talk I will first present the issues involved in object-relational mapping. I will explain how one can implement OO concepts like inheritance on top of relational concepts.

In the second part I will explain how these issues are solved by Tangram, and how you use the module to essentially rid yourself of any persistence concerns. At that point I will give a live demonstration.

Finally I will explain the more interesting Perl techniques that make it possible to build object persistence in a manner that is both orthogonal and efficient (e.g. ties, dynamic code generation, weak references, etc). I will trace in the most interesting parts of the demo.