if (ksm.cfMetaData().containsKey(newName))
throw new ConfigurationException("CF is already defined in that keyspace.");
if (!Migration.isLegalName(newName))
throw new ConfigurationException("Invalid column family name: " + newName);
cfId = ksm.cfMetaData().get(oldName).cfId;
// clone the ksm, replacing cfm with the new one.
KSMetaData newKsm = makeNewKeyspaceDefinition(ksm);
rm = Migration.makeDefinitionMutation(newKsm, null, newVersion);
}