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From "Thomas Dudziak" <tom...@gmail.com>
Subject Re: Additions to generated XML
Date Thu, 21 Feb 2008 18:51:39 GMT
On Wed, Feb 20, 2008 at 11:39 PM, Daniel López <D.Lopez@uib.es> wrote:

>  I don't have a list of databases that use radix, but a quick search says
>  that Oracle and SQLServer have it and the Apache Derby JDBC driver also
>  returns some value for it. HSQLDB on the other hand does not seem to
>  have anything about it in the documentation... or MySQL, or Informix...
>  not sure if it is too common. It seems that the usual values are 10 or
>  2, implying that the length specified by the column is to be interpreted
>  as "number of digits" or "number of bits" to store the value, but it
>  does not seem to be too general.
>
>  We are using Oracle and we came across this attribute so we thought it
>  was more widely used. But from this tiny research, it might not be
>  worthy attacking it now.

I think the JDBC Api was anticipating support here in databases, but
as far as I know, there is no database that actually supports the
specification of a radix for a datatype. E.g. neither Oracle nor Sql
Server nor PostgreSQL allow it as per their datatype spec pages:

http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/sql_elements001.htm#sthref80
http://www.postgresql.org/docs/8.3/interactive/datatype-numeric.html
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/tsqlref/ts_da-db_7msw.asp

Hence I would assume that this value is always 10 for a numeric column
(or perhaps 2 for BIT/BOOLEAN columns).

>  Regarding the Oracle columns, when reading the DB we detected the Oracle
>  version automatically, but I understand that introducing this vendor
>  specific things into a general tool is not too elegant.

Support for detection of a database version via the JDBC driver is
planned for a later release (see
http://issues.apache.org/jira/browse/DDLUTILS-113).


Tom

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