4.2 for the first time exposes generated SQL as an AST, so tweaking it has become much easier. This is the feature that made possible to support geospatial and JSON types.
Nikita, please correct me if I am wrong with the following instructions (as this API is still in flux). So.. To customize produced SQL, you will need to register a custom DbAdapter that returns a custom SQLTreeProcessor. SQLTreeProcessor is a SQL tree walking callback that can change the default tree structure. Your own processor can extend TypeAwareSQLTreeProcessor. See for instance PostgreSQLTreeProcessor for how to change the default behavior. Andrus > On Sep 8, 2020, at 11:12 PM, Hugi Thordarson <h...@karlmenn.is> wrote: > > Working with old DB designs really results in the weirdest questions… > > So… I've been working around a design problem in a customer DB by using my > own BatchTranslatorFactory. The functionality was that if a column is called > "company", every update wraps the column's new value in a coalesce function > to ensure that it's never set to null (for… reasons). This has worked great > as a workaround for our problem. > > However, SQL generation in Cayenne 4.2 is all new so my current solution ( > https://gist.github.com/hugith/a33a20fc7da7fd8f709f59ce3a30a96a > <https://gist.github.com/hugith/a33a20fc7da7fd8f709f59ce3a30a96a> ) doesn't > really port. > Before I start considering migration to 4.2, is this possible to do there? Or > should I just bite the bullet and start fixing up that bloody DB before > upgrading? > > Cheers, > - hugi
