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From Satheesh Bandaram <banda...@gmail.com>
Subject Re: Google SOC:MySQL to Derby Migration tool design question
Date Wed, 12 Jul 2006 22:48:22 GMT
Jean T. Anderson wrote:

>One thing to consider is DdlUtils is database agnostic. For example,
>adding support for "create view" doesn't mean just adding it for Derby,
>but also adding it for every database supported (see the list at
>http://db.apache.org/ddlutils/database-support.html ).
This is important... While ddlUtils goal is to support all databases,
Ramin is attempting to fix his target database to Derby and to make
source database mySQL for his migration utility. (for now) It doesn't
seem like Ramin should take on adding database specific code to ddlUtils
(that DatabaseMetadata might not expose directly) and to test on 13
databases that ddlUtils currently supports.

Here are the issues I see with using ddlUtils

   1. Doesn't support many database objects, like views, procedures,
      functions and check constraints. It may not even be ddlUtils goal
      to support database specific objects that other databases may not
   2. Database migration is likely to require some intervention when
      automatic migration doesn't succeed. When this happens, would
      users have to modify XML files that ddlUtils generates and also
      other schema files that migration utility generates? Doesn't seem
      right... having to modify XML files for tables, but other output
      files for views or constraints etc.
   3. ddlUtils is still under development and has not had an official
      release yet. While it may or may not be stable enough, should
      Derby community vote to include pre-released software into Derby's
      official releases? I, for one, would like to see this mySQL to
      Derby migration in 10.2 release in some form.

It is also possible to develop mySQL specific schema capture (for views
and other objects) just for this utility and then contribute that logic
to ddlUtils project if there is interest. To do complete and successful
migration, some database specific operations must be performed and that
may not be ddlUtils goals for now.


>You might consider posting to ddlutils-dev@db.apache.org to ask what
>level of effort people think might be required to implement the missing
> -jean
>>On 7/11/06, Bryan Pendleton <bpendleton@amberpoint.com> wrote:
>>>>The DdlUtils tool seems not be capable of migrating views, CHECK
>>>>constraints,  and stored procedures. I would like to know what do you
>>>>think if DdlUtils tool can be reused for migrating the tables and
>>>>Indexes, and use the DatabaseMetadata for migrating views and stored
>>>>procedures? .....
>>>Perhaps another possibility would be for you to improve DdlUtils so
>>>that it has these desirable features. The end result would be a better
>>>DdlUtils *and* a MySQL-to-Derby migration tool.

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