I have a Schema called MySchema with a field called Field1 and would like to rename the field to Field2. I did a test and it seems that changing the name of a field does not update the field in Components already deriving from this Schema (related documentation - requires login).
What is the correct way to rename a field and have it change in all derived Components?
When you opened your Schema to edit it, you got a notification indicating that your changes would not be updated in derived Components.
(in 2013 it mentions Changes to this Schema will affect all related items. together with a Show Where Used button, agreed this isn't as clear as it was stated in older versions, but I believe this is the least read message anyways, so no matter what it said, people just don't seem to be willing to read it ;o).
Also the documentation you mentioned specified this with the following note:
Note: Existing items based on the Schema are not automatically updated. For example, if you remove a field from a Component Schema, Components based on that Schema that have a value set for the removed field will continue to contain that value. The value will only be removed when the Component is opened and saved, either in the Content Manager Explorer GUI or when using the Content Porter application.
To update all derived Components, you have to (manually) edit all those Components. On some changes, the UI will already try to fix your changes (like removing values for fields which are no longer in the Schema, or reordering fields according to the Schema), but I don't think a field rename is something that the UI can cater for (apart from the order there is no way of identifying which field you renamed).
So options you have are:
Last thing, which is not a real option perhaps, don't make the change, just change the description of the field in the Schema and leave the XML name as is.
As Bart says, I would strongly recommend that you do this using the core service.
In addition to this, whenever I have done this in the past, I have always done this in two 'passes'. The first pass iterates through all of the Components and just copies the contents of Field1 to Field2. (This then gives chance for testing to take place, whilst maintaining the original content.) The second pass would then remove Field1 and re-save the Components.
Obviously you will also want to fully back-up your Tridion CM database before starting this work.
For some kinds of schema changes, generic tools like the component synchroniser can be used, but for a field rename, you need to take care of it yourself. The obvious technology for this is XSLT. A field name would be a straightforward identify transform plus an explicit template to take care of the field in question.
To execute this, you can just do a where-used on the schema. A while ago I blogged about the poor man's component synchroniser. The example is written against the TOM, but you could easily update it to work against the core service.
