September 26, 2007

Migrating Project Definitions

I've previously written (here, for example) about deleting objects during a migration. When you do a Compare and Report, and an object is listed as "Absent" in the source database and anything other than absent in the target, it will be marked for deletion during the next Copy.

Recently I needed to rename a number of custom Field objects. (Keeping the original names would have worked but would have been very misleading for maintenance purposes.) An object can be attached to a project and then deleted from the database. But in the case of a rename, the object's entry in a project is renamed as well. That means that the object under the original name would remain in the target database. I wanted to delete these old objects. To do this, I logged in to a different environment that included the objects and added them to a new project, then migrated only the project definition—not the objects within the project back to the development environment. Then I merged this project into my main project. Now the main project contains entries for the old field names. These will compare as "Absent" during the next Compare and Report. Since App Designer is afraid to delete an object, I'll then check the Upgrade box next to each field so that the action of Delete will be performed.

A project contains various pieces of information but its main purpose is to act as a list of objects. In unusual situations such as the one described above, Tools allows us to migrate the project itself without carrying along the objects to which it refers. This is done by leaving "Copy Project Definition" checked on the Copy panel, but deselecting all of the object types. To merge projects together, open your main project and then select File | Merge Projects from the menu. Specify the project you want to copy and the objects listed in that project will be added to your project. No objects are actually copied during this operation; their names are just added to the list.

Until next time...