title: Sql Server - changing column from UniqueIdentifier to varchar(128) - backwards compatability?
body: <p>I'm making changes to a Sql Server (2008) database to change an existing column type from a UUID to a varchar(128) - the column, we'll call it <strong>reference</strong> was originally used to save an ID of a reference project that provided more information about the data in the row, but now the business requirements have changed and we're just going to allow free-form text instead.  There were no foreign keys setup against the column, so there won't be any breaking relationships.</p>
  
  <p>My biggest concern at the moment is one of backwards compatibility with existing stored procedures.  Unfortunately, the database is very big and very old, and contains hundreds of stored procs littered throughout the design.  I'm very nervous about making a change which could potentially break existing stored procs.</p>
  
  <p>I know this is a loaded question, but <strong><em>in general</em></strong>, can UUID columns be converted into varchar columns without deleterious effects?  It seems like any existing stored proc which inserted into or queried on the UUID column would still work, given that UUIDs can be represented as strings.  </p>