Can some one give some real time example of how it works since I have no knowledge about stored procedures. Where these procedures to be stored? in the previous version or updated version?
How the data are migrated across?
A stored procedure is just a query stored in the database. You would execute it with executeStoredProcedure in a Servoy method. This method could be triggerred by http too. The SP would already need to be in the old version of the solution so that the new version could make use of it. You would just call it to run and pass it the neeeded parameters like a new table name or column, etc. Then you'd exit servoy to refresh the tables.
Theoretically, you could then do just about anything with teh databsase here. My guess is that you could also use this to get around some of the limitations Servoy puts on modifying tables. Those limitations are in place to protect the db structure in case other there are non-servoy users of the db like a webserver connection, for example. However, now with the headless client, that is probably a little less important. In many environments, the databse may only be serving Servoy.
Anyway, this is a powerful approach and again shows how you can probably do whatever you really need to do with Servoy. You only may need to use some clever SQL or Java or beg Servoy team to build a feature to do the heavy lifting.
I'll be playing with this in the weeks ahead for sure.