How do you test that an Titanium Alloy migration will work?

Question

I'm about to release an app update of an iPhone app that I've written in Titanium Alloy. I've added a new column to the database, so I've written a migration for it. The upwards migration is simple enough, just altering the table to add a new column. However, the downwards migration has be a little worried as it involved creating a temporary database, storing the data I need, and then dropping the existing data base and creating a new one with the stored data, in order to keep remove column.

How do I test that this code is correct and will work?

Here are my migrations:

migration.up = function(migrator) {
    migrator.db.execute('ALTER TABLE ' + migrator.table + ' ADD COLUMN is_sample BOOLEAN;');
};

migration.down = function(migrator) {
    var db = migrator.db;
    var table = migrator.table;
    db.execute('CREATE TEMPORARY TABLE beers_backup(alloy_id,name,brewery,rating,percent,establishment,location,notes,date,date_string,beer_image,latitude,longitude,favourite);');
    db.execute('INSERT INTO beers_backup SELECT alloy_id,name,brewery,rating,percent,establishment,location,notes,date,date_string,beer_image,latitude,longitude,favourite FROM ' + table + ';');
    migrator.dropTable();
    migrator.createTable({
        columns: {
            "name": "text",
            "brewery": "text",
            "rating": "integer",
            "percent": "integer",
            "establishment": "text",
            "location": "text",
            "notes": "text",
            "date": "text",
            "date_string": "text",
            "beer_image": "text",
            "latitude": "integer",
            "longitude": "integer",
            "favourite": "boolean"
        },
    });
    db.execute('INSERT INTO ' + table + ' SELECT alloy_id,name,brewery,rating,percent,establishment,location,notes,date,date_string,beer_image,latitude,longitude,favourite FROM beers_backup;');
    db.execute('DROP TABLE beers_backup;');
};

I'm guessing you don't have the previous app build available? — Stevo Perisic
Unfortunately not, but I could roll back the app using version control and create a build, if that's what I need to do? — shrewdbeans

Stevo Perisic Stevo Perisic · Accepted Answer · 2014-07-03T13:54:14

You should be fine as long as your first migration file (the one you created when you created the model) matches up with the downward migration here.

Like this:

migration.up = function(migrator){
 migrator.createTable({
  columns: {
   "name": "text",
   "brewery": "text",
   "rating": "integer",
   "percent": "integer",
   "establishment": "text",
   "location": "text",
   "notes": "text",
   "date": "text",
   "date_string": "text",
   "beer_image": "text",
   "latitude": "integer",
   "longitude": "integer",
   "favourite": "boolean"
  }
});
};

migration.down = function(migrator) {
 migrator.droptTable();
};

This migration file has to have a timestamp that is less than the one you listed in the original question.

How do you test that an Titanium Alloy migration will work?

1 Answers