ad3) this because how web2py maps its ID field. if we also map ID to a second field (like id2), we can overcome some id limitations.
ad4) GAE has some sort of joins (via references), but otherwise indeed no joins. A GAE database scheme should work with this restriction in mind so joins are not needed. This means that the same db layout cannot be optimized for both GAE and a relation RDBMS. Joins could be perhaps be simulated on python level (same as OR and like), but those will be more expensive. ad 9) GAE supports limited set of transactions, but this is different from how web2py supports it in the end: a GEA db != relational database, and should not be treated as such. The main responsibility for this is with the programmer, and not with web2py. However, web2py is very usable to work with a GAE backend while keeping the limitations and caveats in mind. Hans On Thu, Jun 25, 2009 at 7:05 AM, mdipierro<[email protected]> wrote: > > I like to think of GAE as a relational database without JOINS and > without transactions. > With this limitations and a few caveats the the same web2py APIs that > work for relational databases work on GAE. > > 1) you connect with > > from gluon.contrib.gql import * > db=GQLDB() > > 2) the id is still there but it is an int uuid, not an autoincrement. > This is not a problem since we never use the fact that it is an > autoincrement > 3) you cannot mix queries involving the id and involving other fields. > 4) no joins > 5) no OR > 7) no LIKE > 8) no nested selects > 9) no transactions > 10) no more than 1000 records at the time > > These are all GAE limitations, not web2py limitations. > > Massimo > > On Jun 24, 11:35 pm, "Md.Mahbubur Rasheed" <[email protected]> > wrote: >> Hi, >> I was wondering if there is any way to directly use Google app engine db >> model with web2py. >> >> It is because GAE DB model has few principles that doesn't match with other >> DB. For example there is no default "auto increment" feature what we use in >> mysql regularly. Also I don't know how web2py handle the feature "Each >> entity also has a *key* that uniquely identifies the entity." >> >> Please tell me with a simple example how to do that. >> >> Thank you. > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "web2py Web Framework" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/web2py?hl=en -~----------~----~----~----~------~----~------~--~---
