Tangram::Sucks(3pm)					User Contributed Perl Documentation				       Tangram::Sucks(3pm)

NAME

       Tangram::Sucks - what there is to be improved in Tangram

DESCRIPTION

       Tangram has taken a concept very familiar to programmers in Java land to its logical completion.

       This document is an attempt by the coders of Tangram to summarise the major problems that are inherant in the design, describe cases for
       which the Tangram metaphor does not work well, and list long standing TO-DO items.

       DESIGN CAVEATS

       query language does not cover all SQL expressions
	   Whilst there is no underlying fault with the query object metaphor per se, there are currently lots of queries that cannot be expressed
	   in current versions of Tangram, and adding new parts to the language is not easy.

       some loss of encapsulation with queries
	   It could be said this is not a problem.  After all, adding properties to a schema of an object is akin to declaring them as "public".

	   Some people banter on about data access patterns, which the Tangram schema represents.  But OO terms like that are usually treated as
	   buzzwords anyway.

       HARD PROBLEMS

       partial column select
	   This optimisation has some serious dangers associated with it.

	   It could either be

       no support for SQL UPDATE
	   It may be possible to write a version of "$storage->select()" that does this, which would look something like:

	     $storage->update
		 ( $r_object,
		   set => [ $r_object->{bar} == $r_object->{baz} + 2 ],
		   filter => ($r_object->{frop} != undef)
		 );

       no explicit support for re-orgs
	   The situation where you have a large amount of schema reshaping to do, with a complex enough data structure can turn into a fairly dif-
	   ficult problem.

	   It is possible to have two Tangram stores with different schema and simply load objects from one and put them in the other - however
	   the on-demand autoloading combined with the automatic insertion of unknown objects will result in the entire database being loaded into
	   core if it is sufficiently interlinked.

       replace SQL expression core
	   The whole SQL expression core needs to be replaced with a SQL abstraction module that is a little better planned.  For instance, there
	   should be placeholders used in a lot more places where the code just sticks in an integer etc.

       support for `large' collections
	   Where it is impractical or undesirable to load all of a collection into memory, when you are adding a member and then updating the con-
	   tainer, it should be possible to

	   This could actually be achieved with a new Tangram::Type.

       MISSING FEATURES

       concise query expressions
	   For simple selects, this is too long:

	     ...

       non-ID joins
       tables with no primary key
       tables with multi-column primary keys
       tables with auto_increment keys
       tables without a `type' column
       tables with custom `type' columns
       tables with implicit (presence) `type' columns
       fully symmetric relationships
	   back-refs are read-only.

       bulk inserts
	   Inserting lots of similar objects should be more efficient.	Right now it generates a new STH for each object.

       `empty subclass' schema support
	   You should not need to explicitly add new classes to a schema if a superclass of them is already in the schema.

perl v5.8.8							    2006-03-29						       Tangram::Sucks(3pm)