Convert sqlalchemy core statements to raw SQL without a connection?

Question

I have a script that uses sqlalchemy core, but I unfortunately need to rewrite it to use raw sql instead. Is it possible to translate my sqla insert/etc… statements into a specfic dialect (oracle here) without an explicit engine ?

Essentially, being able to use a non default engine for str(some_sqla_core_expression) ?

Answer 1

any expression becomes a string like this (basically stmt.compile(dialect=dialect)):

from sqlalchemy.sql import column, table, select
from sqlalchemy.dialects import oracle

dialect = oracle.dialect()
table = table('sometable', column('id'), column('data'))
stmt = select([table]).where(table.c.id==5).where(table.c.data=='foo')
raw_sql = unicode(stmt.compile(dialect=dialect))
print raw_sql

There's actually an example of this in the SQL tutorial at the moment here: http://docs.sqlalchemy.org/en/latest/core/tutorial.html#using-joins