一次编写，随处运行

For the sake of the example let us assume that we only want to retrieve the first row. MDB::queryRow() fetches the first row, he frees the result set and returns the content, so it is exactly what we want.
为了作个演示，让我们假定我仅仅想要获取第一行。MDB::queryRow() 获得第一行，它释放结果集并且返回其内容，因而它正是我们所要的。

$result = $mdb->queryRow($query);

But different RDBMS return data like dates in different formats. So, if I then want to do some date arithmetic it is important that data is always returned in the same format regardless of the RDBMS chosen. This can be done semi-automatically by MDB. All you need to do is tell MDB what type your result columns will have and MDB handles the conversion. The easiest way is to pass such information with the query method call:
但是不同的 RDBMS 返回像日期这样的数据时用的格式是不同的。因此，如果我们然后要对一些数据进行计算，不管选择的 RDBMS 是什么，把数据以相同的格式返回是重要的。这个可以由 MDB 半自动地完成。你所有需要做的是告诉你的结果列将是什么样的类型，MDB将处理转换的工作。最简单的办法是把这样的信息传递给查询函数。

$types = array(''timestamp'', ''integer'');
$result = $mdb->queryRow($query, $types);

This tells MDB that the first column of the result set is of the type `timestamp'' and the second is of the type `integer''. All methods that allow querying can take such meta-information as an optional parameter. The data can also be set later using MDB::setResultTypes(). Depending on the database that the data is retrieved from, it will then convert the returned data accordingly. The MDB internal data format for timestamps is the ISO 8601 standard. Other packages such as PEAR::Date can handle this format. MDB also provides a small number of methods for date format conversion in the MDB_Date class that can be included optionally.
这告诉 MDB 结果集的第一列类型是 ''timestamp'' 以及第二列是''integer''。所有查询函数能够接受这样的元信息作为可选的参数。数据还能事后用 MDB::setResultTypes() 来设置。取决于数据获取于的数据库，它然后将被相应的转换返回的数据。MDB 内部的 timestamps 的数据格式是遵循 ISO 8601 标准的。其他像 PEAR::Date 这样的包能够处理这种格式。MDB 还在 MDB_Date 类中提供了一些数据格式转换函数，它们能够被可选的包含。

Since pretty much every RDBMS returns integer data the same way there is no need to convert integer data. So, in order to gain a slight performance improvement you could do the following:
因为相当多的 RDBMS 以相同的方法返回整数数据，没有必要转换整数数据。因而，为了获得稍许的性能改进你能够这么做：

$types = array(''timestamp'');
$result = $mdb->queryRow($query, $types);

This way only the first column of the result set would be converted. Of course this may become an issue if MDB would be used in conjunction with a database that does return integers di

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