@Override
            public List<String> createSql(DbAdapter adapter) {
                StringBuilder sqlBuffer = new StringBuilder();
                QuotingStrategy context = adapter.getQuotingStrategy();
                sqlBuffer.append("ALTER TABLE ");
                sqlBuffer.append(context.quotedFullyQualifiedName(getEntity()));
                sqlBuffer.append(" ALTER COLUMN ");
                sqlBuffer.append(context.quotedName(getColumn()));
                sqlBuffer.append(" NULL");
                return Collections.singletonList(sqlBuffer.toString());