Of course you are right and I agree - nothing solved for the migration problem.
I just saw the opportunity to mention future options, sorry for mixing this in this thread. Good luck with your migration ! B-) > -----Original Message----- > From: Christian Rodriguez [mailto:[EMAIL PROTECTED] > Sent: Tuesday, March 08, 2005 12:09 PM > To: Derby Discussion > Subject: Re: Inserting values in an identity column > > Bernd, your solution doesnt solve my problem AT ALL. It > doesnt solve the problem of migration from other databases to > Derby, which seems to be a very important feature. > > Most databases generate "dumps", either as comma separated > files or as "inserts". Those inserts contain values, even for > identity or "autoincrement" columns. Any reasonable DB system > should be able to take those inserts and restore the values > in the database as a way to migrate from one RDBMS to another. > > The "sequence" feature is a nice feature, but it wouldnt > solve this problem at all: you would have to map every value > in the "dump" file with the value given by the "sequence" and > 'translate" all the references, i.e. a big mess. > > You are trying to solve the problem of "unique identifiers > throughout the database", Im talking about "inserting > specific values in identity columns". They may be related, > but they are not the same problem. > > I just filed a JIRA. Thanks. > Xtian > > > On Tue, 8 Mar 2005 11:55:45 -0600, Bernd Ruehlicke > <[EMAIL PROTECTED]> wrote: > > Yes, but (in my personal opinion) it would be even better > if we had a > > global sequence generator like Oracle, MS SQL etc > > > > See also http://issues.apache.org/jira/browse/DERBY-103 > > > > Than a user does not need to worry about this and just > create a usual > > colum which will support altering. The price is of course that you > > have to insert the value yourselfe into this coulm but you may than > > use a function like "mySequence.nextval". This makes also > sure that > > every single row in your database (if each table has an > identity) has > > a unique key - in all of the database. This becomse pretty > handy if a > > table holds the key and name of other table(s) - generically. Like > > > > MyTable > > table_id VARCHAR > > ... > > Source_ID VARCHAR (if a text string is used as sequence key) > > Source_Table VARCHAR (name of source table) > > ... > > ... > > > > If you only had column identifiers you will have scenarious where > > "Source_ID" is the same for 2 differnt tables ! That is not > possible > > when using a global sequence. > > > > ... anyhow ... just some words for discussion. > > > > B-) > > > > > > > -----Original Message----- > > > From: Kathey Marsden [mailto:[EMAIL PROTECTED] > > > Sent: Tuesday, March 08, 2005 11:38 AM > > > To: Derby Discussion; Derby Development > > > Subject: Re: Inserting values in an identity column > > > > > > Christian, > > > > > > Could you please file a Jira entry for this? I am hoping there > > > someone in the Derby development community that has time > to take up > > > this issue and propose and implement a solution. It seems to me > > > that this is a serious hindrance to migration to Derby > that would be > > > good to resolve sooner rather than later. > > > > > > You can file it as an "Improvement" in Jira at: > > > http://issues.apache.org/jira/secure/CreateIssue!default.jspa > > > > > > Thanks > > > > > > Kathey > > > > > > Trevor Squires wrote: > > > > > > > Hi, > > > > > > > > I asked this very question last week (or so) for pretty > > > much the same > > > > reason. > > > > > > > > It doesn't appear that you can alter the table to make it > > > an identity > > > > column after creation (which was my first idea). I was > > > also unable to > > > > find any way to switch off the identity feature > temporarily either. > > > > > > > > One person suggested that derby ought to support something like > > > > "generated by default as identity" which makes sense - although > > > > I'd rather be able to just switch on and off the > current behavior > > > > for loading of dumps and pre-population. > > > > > > > > In order to get my project out the door I ended up > converting the > > > > logic to update/select rows in an "identities" table > that I manage > > > > myself. > > > > > > > > HTH, > > > > Trevor > > > > > > > > Christian Rodriguez wrote: > > > > > > > >> Hi everyone, > > > >> > > > >> I am trying to import data from a mysql dump file. > > > Basically, I need > > > >> to insert values in tables. Some of the tables in > mysql include > > > >> auto_increment columns, that I have translated to > > > "generate always as > > > >> identity" in derby. Now... the mysql dump file has values in > > > >> those columns, and I get an error when trying to > insert a value > > > >> into an IDENTITY column in derby. How can I do this? > > > >> > > > >> I have a couple of ideas, but none work: > > > >> > > > >> 1. I could define the column as a regular column (not > > > identity) and > > > >> after the values have been populated I could try to ALTER > > > the column > > > >> in the table to make it an identity column, but this last > > > part doesnt > > > >> seem posible. > > > >> 2. Is there another way to implement "autoincrement" in derby? > > > >> 3. Is it posible to disable the "identity" feature until > > > all values > > > >> have been populated? > > > >> > > > >> Any other ideas? > > > >> > > > >> Of course, I could let derby generate values for that > > > identity column > > > >> and then map the original values with those, and touch all the > > > >> references in the other tables and convert them to the new > > > identity > > > >> values, but that doesnt seem like a lot of work... and Im > > > getting the > > > >> feeling there should be a more reasonable way to import > > > "dumps" from > > > >> other databases... > > > >> > > > >> Thanks for any help you can give me, Xtian > > > > > > > > > > > > > > > > > > > > >
