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From Satheesh Bandaram <sathe...@Sourcery.Org>
Subject Re: SQL/DDL Limitations (and DB2)
Date Mon, 20 Sep 2004 20:40:20 GMT
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I did some searching on the internet. I found this table about some of
the DDL maximum lenghts. (Haven't verified) If Derby increases
constraint name length to 128, looks like it would break application
migration to both Oracle and DB2, the top two enterprise databases.<br>
<br>
While increasing the limit makes life easier to migrate applications to
Derby, wouldn't it make it harder to migrate out of Derby to enterprise
databases? Being a free Apache product, Derby might actually have to
pay attention to both migration routes ...<br>
<br>
Satheesh<br>
<br>
<table border="1" cellpadding="2" cellspacing="2" height="191"
 width="536">
  <tbody>
    <tr>
      <td valign="top"><b>Identifier maximum length (characters)</b><br>
      </td>
      <td valign="top"><b>Oracle 9</b><br>
      </td>
      <td valign="top"><b>DB2 8.1</b><br>
      </td>
      <td valign="top"><b>SQL Server 2000</b><br>
      </td>
    </tr>
    <tr>
      <td valign="top">Table name length </td>
      <td valign="top">30<br>
      </td>
      <td valign="top">128<br>
      </td>
      <td valign="top">128<br>
      </td>
    </tr>
    <tr>
      <td valign="top">Column name length</td>
      <td valign="top">30<br>
      </td>
      <td valign="top">30<br>
      </td>
      <td valign="top">128<br>
      </td>
    </tr>
    <tr>
      <td valign="top">Constraint name length<br>
      </td>
      <td valign="top">30<br>
      </td>
      <td valign="top">18<br>
      </td>
      <td valign="top">128<br>
      </td>
    </tr>
    <tr>
      <td valign="top">Index name length </td>
      <td valign="top">30<br>
      </td>
      <td valign="top">128<br>
      </td>
      <td valign="top">128<br>
      </td>
    </tr>
    <tr>
      <td valign="top">Number of table columns<br>
      </td>
      <td valign="top">1000<br>
      </td>
      <td valign="top">255<br>
      </td>
      <td valign="top">1023<br>
      </td>
    </tr>
  </tbody>
</table>
<br>
Jason Rimmer wrote:<br>
<blockquote cite="mid414DC322.2000102@irth.net" type="cite">&nbsp;&nbsp;&nbsp;&nbsp;While
a
reasonable suggestion on its face adoption puts Derby on a slippery
slope.&nbsp; Why favor DB2?&nbsp; Why not add transition flags for any
'enterprise-class' database such as P determine a destiny of its own.
(Though I understand that such a determination could lead to the
maintenance of these DB2 compatibility flags).
  <br>
&nbsp;<br>
Joel Rosi-Schwartz wrote:
  <br>
  <blockquote type="cite">I am just guessing that IBM would be less
than overjoyed if Derby lost its ability to be an easy migration path
to DB2. Would it not be fairly reasonable, however, to fulfil both
requirements. At database creation time a flag could be set to dictate
DB2 mode or extended mode. The database could then set an immutable
database level property and behave accordingly. True this would
introduce some complexity into the system, but it would be politically
sensitive while still achieving better functionality.
    <br>
    <br>
- joel
    <br>
  </blockquote>
  <br>
</blockquote>
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