Changing a string field to LOV using TriDK

Question

I am trying to change the field type from a string field to a LOV, and running into issues. Does anyone have any experience with change field types? I get the following error

<tridk:error tridk:errorcode="TooManyValues">The Fieldtype and/or the FieldAssist can only be changed when there are no values.</tridk:error>

Dave De Meyer · Accepted Answer

Converting the type of an existing field is not supported. When the field holds no instances (so values), then you can simply drop the field and recreate it with the better field type. 
When the field is already used indicated by "TooManyValues", then uncontrolled string values have to be mapped to controlled LOV values. Best way to achieve that is by creating a new LOV-linked field and run a migration on it. Either through a custom API automation program, something simple using github.com/.../ISHRemote , or the plugin system or... Your options depend on the version of the software and of course the size of your legacy values.

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Changing a string field to LOV using TriDK