There is no way to do this within the Delphi VCL. Seems like a pretty
serious omission to me. However, it is possible to do it by talking
directly to the Borland Database Engine through the interface provided by
the DBIPROCS and DBITYPES units. You call DbiDoRestructure, but set all the
"number of" variables to zero, which makes it leave the existing values
intact. I have code to do this, but it's a bit too long to included here.
E-mail if you want it.