Groups > comp.lang.java.databases > #245

Re: Difference in JDBC re

From	"Martin Gregorie" <martin.gregorie@THRWHITE.remove-dii-this>
Subject	Re: Difference in JDBC re
Message-ID	<gadla1$c87$2@localhost.localdomain> (permalink)
Newsgroups	comp.lang.java.databases
References	<317dcb86-f935-45ca-afbc-15f8e63252b2@d77g2000hsb.googlegroups.com><cd5a8be
Date	2011-04-27 15:22 +0000
Organization	TDS.net

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  To: comp.lang.java.databases
On Thu, 11 Sep 2008 15:50:27 -0700, Tom Cole wrote:

> On Sep 11, 6:45-apm, 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       |

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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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