database-versioning

Hi i am creating an app which stores the password of the user entering. and whenever he needs to change his password then the data has to be changed. The problem i am facing is while i am calling the DBHelper class (i created to do all my database works) its not deleting the table if it is available. It will be more helpful if someone tells me how to delete the entries in the table while calling the DBHelper class. I realized that the OnCreate and OnUpgrade functions are not executing except the first time while creating the database. also changing database version automatically also helps i

My question: Should I roll my own model versioning or use one of the versioning gems that's already out there? If I should use a gem, which one seems best for this application? Info about my app My app is a simple Checklist app. There are Checklists and Jobs, and I track user responses with Responses and Submissions. The Response tells me what the use said ("Done", with a note "We need more mops.") and the Submission tells me when that particular Checklist was filled out (because there may be many submissions and sets of responses for a given checklist). I'll show my associations below, in

For my application I have to support update scenarios and the database might be affected. I want to be able to update from an old version to the newest without installing intermediate versions. E.g. Suppose I have version A (the oldest), B (intermediate) and C (new version). I want to be able to update version A straight to version C. For the application files this is simple, I just replace the old with the new ones. However for the database I do not wish to generate a SQL Script to change the database schema from A straight to C, instead I want first apply a script to change the schema from A