db-ddlutils-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Thomas Dudziak" <tom...@gmail.com>
Subject Re: Preventing tables from being dropped
Date Sat, 14 Apr 2007 23:58:33 GMT
Hi Guido

On 4/12/07, Guido Schreuder <g.schreuder@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

    StringWriter buffer = new StringWriter();

    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();

    return getAlterTablesSql(...);

hope that helps,

View raw message