Re: Preventing tables from being dropped

[callme_sanjay <ca...@yahoo.com>]

Hello All,

I am facing similar problem , 

Want to update the database but do not want to touch the other tables 

Tried the solution mentioned in the "thread" but it;s not working ..

Do I need to any other care while doing it.

Please reply 

Regards
-Sanjay


Guido Schreuder-2 wrote:
> 
> Hi Tom,
> 
> Yep, that'll work, i was thinking along the same line already
> 
> thanks,
> Guido
> 
> On Sat, 2007-04-14 at 16:58 -0700, Thomas Dudziak wrote:
>> Hi Guido
>> 
>> On 4/12/07, Guido Schreuder <g....@xs4all.nl> wrote:
>> > I am looking for a way to prevent tables from being dropped when
>> > executing Platform.alterTables(Database, boolean)
>> >
>> > The reason for this is that my model is iteratively constructed without
>> > prior knowledge of the final model. Currently this will lead to
>> > "unknown" tables being dropped, causing data to be lost.
>> >
>> > An option like would be welcome, but maybe being able to somehow
>> > decorate the SqlBuilder and/or ModelComparator might yield a more
>> > flexible solution. Although the latter would probably not be trivial.
>> 
>> Unfortunately, you can't at the moment, at least not out of the box
>> (but a feature request in JIRA would be appreciated).
>> However, you might be able to achieve what you want by using a
>> modified version of e.g. the
>> PlatformImplBase#getAlterTablesSql(Connection, String, String,
>> String[], Database, CreationParameters) method. More precisely, if you
>> do the following:
>> 
>> String   sql          = null;
>> Database currentModel = readModelFromDatabase(connection,
>> desiredModel.getName(), catalog, schema, tableTypes);
>> 
>> // Filter the read model here so that only relevant tables are in the
>> currentModel
>> 
>> try
>> {
>>     StringWriter buffer = new StringWriter();
>> 
>>     getSqlBuilder().setWriter(buffer);
>>     getSqlBuilder().alterDatabase(currentModel, desiredModel, params);
>>     sql = buffer.toString();
>> }
>> catch (IOException ex)
>> {
>>     // won't happen because we're using a string writer
>> }
>> return sql;
>> 
>> 
>> The alterTables is nothing more than a wrapper around getAlterTablesSql:
>> 
>> Connection connection = borrowConnection();
>> 
>> try
>> {
>>     return getAlterTablesSql(...);
>> }
>> finally
>> {
>>     returnConnection(connection);
>> }
>> 
>> hope that helps,
>> Tom
>> 
> 
> 
> 

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