"Dennis Lee Bieber" <wlfr...@ix.netcom.com> wrote in message news:8d747a5biq4rc559tvgju088508bp0o...@4ax.com... > On Sun, 23 Nov 2014 10:21:48 +0200, "Frank Millman" <fr...@chagford.com> > declaimed the following: > >> >> >>The default is for sqlite3 to ignore foreign key contraints. >> [...] >> >>Unfortunately it has a limitation, which they acknowledge but they say is >>unlikely to be addressed. You can access more than one database >>concurrently >>by using the 'attach' command, and qualifying a remote tablename as >>{database} dot {tablename}. You can then include the remote table in any >>sql >>command. However, it will not enforce foreign key constraints across >>databases. >> > Seems acceptable-- as such enforcement would require it to > automatically reattach (likely in both directions) any/all attached > databases when a change is made. Imagine the thrashing if one has some > master database in a read-only mode for most users, and each user has some > child database referencing some field in the master... And the owner of > the > master database deletes a record... > > Are they suddenly going to have to have update capability on every > user's database to check/enforce multi-db references?
I will explain why such a feature would have been useful for me. My accounting system handles multiple companies. I needed to figure out a way to keep each one's data separate from the others. Originally I supported two databases - PostgreSQL and Sql Server. They both have a concept called 'schemas', which handles my requirement elegantly - each company's data is stored in its own schema. When I decided to add sqlite3 as a third option, I found that they did not have 'schemas'. However, I could get very close by creating multiple databases and using 'attach' to access them from one central database. Overall I have been very impressed with how 'complete' sqlite3 is. The limitation mentioned above is one of the few compromises I have had to make. The sql syntax used by PostgreSQL and sqlite3 is virtually identical. I found more variations between PostgreSQL and Sql Server. Frank -- https://mail.python.org/mailman/listinfo/python-list