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Re: Difference in JDBC re

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  To: comp.lang.java.databases
On Sep 12, 7:54 am, Martin Gregorie
<mar...@see.sig.for.address.invalid> wrote:
> On Thu, 11 Sep 2008 15:50:27 -0700, Tom Cole wrote:
> > On Sep 11, 6:45 pm, Tom Cole <tco...@gmail.com> wrote:
> >> We're using jTDS to connect to a backend SQL Server 2000 instance. The
> >> connection is working fine.
>
> >> What we want to do is write a utility that will calculate maximum row
> >> size for each table in a given database. The script we're using looks
> >> something like this:
>
> >> Any ideas what I'm doing wrong here?
>
> It looks to me as if your code is calculating the amount of space needed
> hold the data in a row but is ignoring overheads introduced by the DBMS
> such as padding between columns, index structures, length indication for
> a variable length column, etc.
>
> As the overheads are implementation specific its probably not possible to
> calculate them using information returned by JDBC and almost certainly
> impossible to write a general solution. If the information can be
> retrieved at all it is likely to be in system tables which vary wildly in
> number, content and name between database implementations.
>
> --
> martin@   | Martin Gregorie
> gregorie. | Essex, UK
> org       |

Yeah and the bigger problem I will have is that this will be deployed
on SQL and Oracle installations which also differ wildly.
Unfortunately I just don't know how to go about estimating how much a
new row will cost me in a table.

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Difference in JDBC result "Tom Cole" <tom.cole@THRWHITE.remove-dii-this> - 2011-04-27 15:22 +0000
  Re: Difference in JDBC re "Martin Gregorie" <martin.gregorie@THRWHITE.remove-dii-this> - 2011-04-27 15:22 +0000
    Re: Difference in JDBC re "Tom Cole" <tom.cole@THRWHITE.remove-dii-this> - 2011-04-27 15:22 +0000
      Re: Difference in JDBC re "Silvio Bierman" <silvio.bierman@THRWHITE.remove-dii-this> - 2011-04-27 15:22 +0000
        Re: Difference in JDBC re "Tom Cole" <tom.cole@THRWHITE.remove-dii-this> - 2011-04-27 15:22 +0000
  Re: Difference in JDBC re "Martin Gregorie" <martin.gregorie@THRWHITE.remove-dii-this> - 2011-04-27 15:22 +0000

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