On 04/28/2011 05:24 AM, Iain B. wrote:
I’ve an existing MySql database, and not having used any of the major database
gems like ActiveRecord, Sequel etc etc I was wondering which one would work well
against an already built DB ?
The quicker I can get up and running the better. It would also be nice if I
could bypass whatever sugar it has to run SQL directly, so I can just plug in any
exising queries that are lying around.
Sequel and AR will both let you drop to the SQL level, if the model
level isn’t quite right for what you want to do. I don’t know about
DataMapper or other ORMs.
One thing I’ve always liked about sequel is that there is an
intermediate level, between models and SQL: datasets with their chained
query methods. Some examples:
The documentation for datasets:
Rather than use models, I often find it easier to think in relational
terms and code in ruby, and that’s what sequel’s datasets let you do.
Another factor to consider, when the database precedes the app, is
whether the ORM layer supports the schema. IIUC, AR doesn’t support
composite primary keys without using an extra library. Sequel does
support composite primary keys (this was very helpful to my team just in
the last few weeks). This difference may not matter much, but it’s
something to be aware of.
More on sequel’s differences from AR: