It's hard to say. For my application, the end-user creates the tables. Most users are fine with the 1,012 limit but some "power" users will have extremely large datasets. I imagine that a few thousand would be fine.
In looking through documentation of other database systems it looks like MySQL allows for 2,599 columns. MS SQL Server allows 1,024 for a non-wide table and 30,000 for a wide table. Thanks, Patrick -----Original Message----- From: Kristian Waagan [mailto:[email protected]] Sent: Friday, May 25, 2012 4:21 AM To: [email protected] Subject: Re: limit on the number of columns On 24.05.2012 23:33, Patrick Meyer wrote: > That would be excellent! I think it would be a great feature to have > in Derby. Hi Patrick, Can you say anything about how many columns would be needed to support these use-cases? Are we talking about a few thousand, ten thousand, or even more columns? Regards, -- Kristian > > Patrick > > -----Original Message----- > From: Rick Hillegas [mailto:[email protected]] > Sent: Thursday, May 24, 2012 12:08 PM > To: [email protected] > Subject: Re: limit on the number of columns > > On 5/24/12 4:26 AM, Patrick Meyer wrote: >> I am aware that Derby has a limit of 1,012 columns for each table, but >> many users of my application (it is a program for statistical >> analysis) have very large files that go well beyond this number of >> columns. Does anyone know of a strategy for using multiple tables to >> present one large "virtual" table to end users? Is there a way to >> chain tables together to have an endless number of columns? Is this >> something that can be done through SQL statements? Any advice, >> examples or documentation on such a strategy would be greatly >> appreciated. >> >> Thanks, >> >> Patrick >> > Hi Patrick, > > This appears to me to be an arbitrary limit in Derby, one which we could > investigate lifting. To track this issue, I have filed > https://issues.apache.org/jira/browse/DERBY-5781. This kind of change would > have to appear in a feature release. The 1012 limit also applies to the > number of columns in a SELECT list. This is another arbitrary limit which we > should consider lifting: > https://issues.apache.org/jira/browse/DERBY-5782 > > Thanks, > -Rick >
