public override string ChangeColumnName(IColumn fromColumn, IColumn toColumn) {
var sql = new StringBuilder("alter table ");
this.AppendQuotedTableName(sql, toColumn.Map);
sql.Append(" change ");
this.AppendQuotedName(sql, fromColumn.DbName);
sql.Append(" ");
this.AppendQuotedName(sql, toColumn.DbName);
this.AppendColumnSpecificationWithoutName(sql, fromColumn);
return sql.ToString();
}