Re: pg_dump of only the structure from a client such as ruby

On Aug 5, 2007, at 18:58 , Perry Smith wrote:

> I find it odd that you are resistant to the idea.  To me, the  
> advantages are clear if it can be done without a tremendous amount  
> of work.  Why horse around with the environment variables to set  
> such things as password, call sh, just to call pg_dump.

My resistance was to the idea that creating a connection through  
ActiveRecord was preferable to a system call.

I believe that pg_dump/psql are only required if you're using  
config.active_record.schema_format = :sql. (I may be mistaken, as I  
exclusively use schema_format = :sql so any other possible dependents  
are already satisfied.)

When using config.active_record.schema_format = :sql, pg_dump and  
psql pretty much need to be in your path. And if psql is already in  
your path, psql can be used with the -c flag to run arbitrary  
commands (such as CREATE/DROP DATABASE and also CREATE ROLE), so  
createdb and dropdb are not really necessary for most purposes. Of  
course, you still need a database to connect to. Personally, I don't  
want to put postgres/template1 connection information in database.yml  
for security reasons: these commands are not run very often and a  
great way to keep information secure is to not have it available.  
Personally I wish Rails did not include database.yml by default as I  
think it's much too easy to load it into an SCM repository. I use a  
custom rake task to set up the Rails application to take care of this  
as well as other details, including database and role creation. (This  
is especially helpful for running tests.)

If you're not using config.active_record.schema_format = :sql, then  
perhaps pg_dump and psql are not required, and they aren't  
necessarily in your path. In that case it might make sense to use  
ActiveRecord for CREATE/DROP DATABASE as you aren't necessarily going  
to have psql otherwise in your path. However, in this case in my  
opinion it's better for the above-mentioned security reasons not to.

Michael Glaesemann
grzm seespotcode net