Re: mysql Compare with postgres? (Re: Advice needed on large database project)

In article <m2207r89lg.fsf_at_subject.cynico.com>, Craig Brozefsky <craig_at_onshore.com> wrote:
>
>psmith_at_baynetworks.com (Paul D. Smith) writes:
>
>Hmm, no primary keys? No multi-table indexes(indexing two or more
>fields across table,s or indexing two or more fields alone) without
>having to write a bunch of SQL and make surrogate types. I have yet
>to see anything about outer joins(are they there at all?), no
>triggers(well you can rewrite functions). On the other hand it's
>free.

True, primary keys are not supported by postgreSQL, but it really is not necessary as every record is assigned a unique identifier. This identrifier (called an oid (Object IDentifier)), is returned by insert commands, and can be used as a primary key value to uniquely identify the column. Another way of accomplishing this is to use a UNIQUE index on the field. This will prevent you from inserting a duplicate value into that field. In v6.1 (which is due out in about 2 weeks), there is a "SEQUENCE" code, which when used with a unique index will be the exact same thing as a primary key which automatically increments each time an insert is done. However, I dont think this is all that big of a deal as the oid works fine as a primary key and for establishing relations between tables.

As for multi-field indexes and joins, these features are in the v6.1 beta, and will be supported in release v6.1. Im not familiar with triggers, so I cant speak about them :). Does that work something like the "notify" idea in postgreSQL? Just curious :). Anyways, v6.1 will at least solve a few of these problems ;). postgreSQL is a little bit different than some other database systems out there, but if you give it enough time to figure it out it turns out to be quite powerful.

But, as you said, you have to have the right tool for the job. Both postgreSQL and MySQL have their strengths and weaknesses. They both are worth looking into.

Regards,
Mike

-- 
Hal 9000 - "Put down those Windows disks Dave....  Dave?  DAVE!!"