On Fri, 27 Apr 2007 14:19:57 -0400, Mike Orr <[EMAIL PROTECTED]> wrote:
> Is it possible to make a mapper class that loads & modifies only some > fields in a table rather than all the fields, yet still autoloads the > fields rather than having hardcoded column types? I've been avoiding > the ORM because frequenty I want to iterate every record without > loading some large text fields, and to avoid 20-line SELECTS in the > log which make debugging less convenient. Yet now I have a > data-conversion project and have been charmed at the ability to load > an object, modify and flush it, without having to do "SELECT" + > "UPDATE ... WHERE". > > When I brought this up previously (in a read-only context), somebody > suggested mapping a Select rather than a Table. That worked but it > led to "select of select" or "select of select of select", which > performed considerably worse than building a query dynamically (by > calling a function to to create the query and set the field list, and > then calling .append_whereclause several times). > > What I'd like to do is pass a list of column names to the Table > constructor and have it autoload those and ignore the others. I > couldn't find an argument for this. Alternatively I could autoload > the table and then delete the undesired columns via a list > comprehension, but it looks like that would involve modifying private > attributes with possibly unintended consequences. you could autoload a table in one metadata, and create a table in another metadata (thats used for the application) selectively adding filtered columns. also the sqlalchemy list has moved to google groups. hth, kapil ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Sqlalchemy-users mailing list Sqlalchemy-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/sqlalchemy-users
