Kevin Teague
Posts: 15
Nickname: wheat
Registered: Mar, 2006
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Re: Gavin King: In Defence of the RDBMS
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Posted: May 27, 2007 4:45 PM
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Having used the ZODB (Zope Object Database), a Python object database,
for many years, as well as a number of relational databases/ORMs, I thought
I'd respond to some of these points from the perspective of a Python
developer.
complexity
There is a lot of complexity in using a relational database
with an ORM. Keeping a seperate RDBMS running, configuring, learning and
optimizing the ORM. It's a lot more code than an ODB.
The converse is that it's that understanding a relational database schema is
a ubiquitous skill, so you can have increased developer complexity in
understanding the modeling of objects.
It can be a real joy to just work with objects though, as you have to much
less thinking about how to persist those objects. You are also free to
make your objects as complex as you desire, complex issues such as model
inheritance and complex attributes are just handled so cleanly.
performance
This is really going to depend upon what your data model
looks like. Sometimes object databases will perform better and sometimes
relational databases will outperform better. It seems like there are some
rather pointed benchmarks that set off Gavin to posting his rant, and any sort
of statement such as "object databases are X times faster than relational
databses" is just silly.
It is worth noting that the ZODB can run in-process or stand-alone,
listening on a TCP/IP port, just like a RDBMS. This kind of flexibility is a
good benefit if you ever need to deploying a client application that needs
it's own local persistence.
You can scale the ZODB across as many servers as you need using ZEO
(Zope Enterprise Objects), and have mutliple redundant primary object stores.
All following the same principals as a RDBMS. Object databases by their nature
do make it much easier to handle changes to the schema across your database
cluster though.
integration
It really depends upon what kind of system you are building,
but when I use the ZODB it's often to support a web application, where you are
going to need some a web service API. Often these are more democratic than a
relational database, as they are often easier to expose outside your internal
network.
Conversely, many people are still much more familiar with SQL than web
services, and SQL gives you a very good 'for free' API, so this just comes
down to the nature of your particular projects goals.
I have also witnessed the curious nature of how the management of even
smaller relational databases can end up falling across multiple
departments. Developers whose hands are tied because management of relational
databases is handled by another group. Where as object databases are not
recognized as a 'database', and so other developers using that technology
are free to manage their data as they see fit (for better or worse).
security
This is a good benefit for object databases, as they are
inherently more secure than a relational database, as you do not have to worry
about SQL injection attacks.
enterprise
The ZODB has been around for about 8 years, so it's
reasonably mature. It is always a trade-off, as tools for working with it are
just not going to compare to the ecosystem that has grown up around Oracle
or MySQL.
The ZODB is the data storage for Plone, which is making it's way into a few
enterprise-sized organizations. There are a few of Fortune 500 companies using
this technology, so while adoption of object database technology in the
enterprise is low, it's not zero. This is partly a political thing, if your
organization has invested X millions of dollars in a J2EE/Orcale solution,
and you come out and say, 'we replaced a relational database backed stack
with an object database one, and we got much better performance with the
object database backed technology', when you next go back to your vendors to
renew your contracts, they aren't going to be so eager to negotiate on price.
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