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On Jan 18, 2008 10:31 AM, <[hidden email]> wrote: > Well, the first thing to do is shut down the old site and redirect it to > the new site so new conflicts no longer happen. Yup, already did that. Old website (even though DNS is updated) points to new DB. > The second thing to do is decide if this can be done with the site down or > with it running. If it is down, you can take your time. I strongly suggest > shutting in down while the process is in progress, but you can dump old > and new databases and create a work/test environment. Needs to be live > On the test environment, you are going to see what the conflicts are. If > they are trivial, no problem, do it by hand, if not.... > > Make sure you have shut off the old site and used a redirect to the new > site, then your problem is merely extracting (1) unique data from the old > site and (2) resolving conflicting data from the new site. > > Load both databases into mysql, but rename the old tables to > old_table.(substituting the actual table name for "table") Find the stuff > that is not in "table" that is in "old_table. Probably use a left outer > join and a where right col is NULL. > > This will get you the stuff that is unique in the old things. You can save > the diff tables as stuff that can be added the the new tables without much > fuss. > > The next query is something like this > > create table wasis_table as select table.id as is, old_table as was where > [some fully unique qualifiers]. > > This will create a was/is for remapping non-unique ids. > > lastly IDs that are only in the old database should be assigned new IDs. > > Well, I could go on and on, but basically you work on an off-line snapshot > of the two databases, and produce a series of scripts that you can apply > to new databases. > > I've had to do it before on a couple systems and there is no easy way, > even when you have redo logs ala oracle.
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