Re: best practice for handling database schema changes

[Aristedes Maniatis]

Interesting article. We implemented something similar, but without hard coding the SQL to update the schema into Java. Instead we have a folder full of files named 1.sql, 2.sql, etc. Each one contains the SQL required to update the database schema. Every time the server application runs it reads a special table in the database with one column and one record. That value is the 'schema version' from the last launch of the application. If this number is lower that the largest xx.sql file in the folder, then that sql file is executed and the version updated.

Ari Maniatis


On 02/12/2006, at 12:56 AM, Michael Gentry wrote:

We do all this before Cayenne is intialised in any way in our application. The only thing we haven't yet done is to write a junit test that validates the sum total of all our incremental updates is the same as a single SQL export from the current Cayenne model.

I found this yesterday (although I haven't read it all yet):

http://www.stepwise.com/Articles/2005/DBChanges/index.html

Not sure if it'll be helpful, but it looks similar to some ideas I had
been pondering in the past.

/dev/mrg


On 11/30/06, Michael Gentry <[EMAIL PROTECTED]> wrote:

Currently you have to manually merge the changes just as you states.
I should probably make an FAQ for this ...

Thanks,

/dev/mrg



>
> hi,

> cayenne mapping was created?

> add flattened relationships, etc.

> current model/mapping?
>
> thanks
>
> Tobias

On 11/30/06, Tobias SCHOESSLER <[EMAIL PROTECTED]> wrote: > What is the best practice for handling changes to the database schema once a > We use the 'reverse engineer from database' feature to create an initial > mapping. But then we usually have to do manual changes like map some pks, > If then the database schema needs to be changed we usually have a problem as > 'reverse engineer from database' overwrites everything. There seems to be > the possibility to replace only selected tables but if you do this the > relationships are messed up. Is there a way to merge the changes with the

-------------------------->
ish
http://www.ish.com.au
Level 1, 30 Wilson Street Newtown 2042 Australia
phone +61 2 9550 5001   fax +61 2 9550 4001
GPG fingerprint CBFB 84B4 738D 4E87 5E5C  5EFA EF6A 7D2E 3E49 102A

PGP.sig
Description: This is a digitally signed message part