A view is kind of a special SQL select statement - so maybe this THIS could be included as part of the DAL... that would actually be the right way to let people easily map from web2py (I don't know why I didn't think of that before). You can make a aview be a temporary table (I don't know what the performance implications for the various dbs are for temporary vs. persistent view - I know is some cases a view is basically an SQL select statement that runs at each access).
so something like SELECT foo as bar from MY_TABLE is the general idea... View syntax (some examples): http://www.postgresql.org/docs/8.2/interactive/sql-createview.html http://dev.mysql.com/doc/refman/5.0/en/create-view.html http://dev.mysql.com/doc/refman/5.0/en/view-syntax.html http://www.sql-server-performance.com/articles/dba/view_basics_p1.aspx http://www.sqlite.org/lang_createview.html http://www.sqlite.org/omitted.html http://www.dba-oracle.com/concepts/views.htm http://publib.boulder.ibm.com/infocenter/dzichelp/v2r2/index.jsp?topic=/com.ibm.db29.doc.intro/db2z_views.htm Did I miss any? Regards, Yarko On Wed, Mar 11, 2009 at 3:54 PM, mdipierro <mdipie...@cs.depaul.edu> wrote: > > Can you point us to an example of how to make a view? > > On Mar 11, 3:48 pm, Yarko Tymciurak <yark...@gmail.com> wrote: > > in essence, web2py imposes a standard, consistent primary key for all > web2py > > tables... > > This is not bad. > > > > I still argue (and the more I think of it, the more strongly) that this > > mapping for operating w/ legacy, existing databases should NOT be handled > by > > web2py --- rather, the DB is the place to handle this. > > > > Make a VIEW in your DB. > > > > It's a db / connection specific issue by definition (so that strongly > > suggests it does NOT belong in web2py); > > It's something any DB can handle already (no need to re-invent an > existing > > wheel); > > In sqllite (probably mostly an issue if you're working on an embedded > > system), the view is READ ONLY, and even this is not a bad thing. There > > are ways around it in sqlite; > > > > The more I hear this discussion (and it has been - in one way or another > - > > going on for maybe a year...) the more two things settle for me: > > > > - I REALLY like the idea of mapping existing databases so that you can > > interface them with web2py; > > - I REALLY think this mapping belongs in the DB --- NOT in web2py code. > > > > Yarko > > > > On Wed, Mar 11, 2009 at 11:15 AM, mdipierro <mdipie...@cs.depaul.edu> > wrote: > > > > > It is more than a convenience. What if the user types an unprintable > > > character in the ISBN? The database would take it but it would be > > > nearly impossible to get to the record. You can have other unique > > > fields in web2py, but you must also have the ID. > > > > > On Mar 11, 11:08 am, DenesL <denes1...@yahoo.ca> wrote: > > > > On Mar 11, 9:56 am, mdipierro <mdipie...@cs.depaul.edu> wrote: > > > > > > > Should the record id be assigned by the DB or by the user? I > > > > > think it should be assigned by the DB. The practical issue is that > > > > > SQLFORM assumes the current record id. You change that and > everything > > > > > break. It can be fixed but web2py will become much more bloated. I > > > > > believe having an autoincrement id should be considered good > practice > > > > > and enforced by web2py. > > > > > > Record id is just a convenience, you can get to a specific record > > > > using its primary key(s) and that is how most tables are normally > > > > built. > > > > So, e.g. the ISBN number can be a primary key in a books DB and there > > > > is not much difference (unless I am failing to see something) between > > > > using it or using an extra id field. > > > > When the primary key consists of several fields the id-ing can be > done > > > > using a list. > > > > I honestly don't know how much bloating can this produce. > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "web2py Web Framework" group. To post to this group, send email to web2py@googlegroups.com To unsubscribe from this group, send email to web2py+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/web2py?hl=en -~----------~----~----~----~------~----~------~--~---
