Partitioning across multiple databases wouldn’t be a big deal if it were not for the fact that cross-database queries are not supported, forcing any unions or joins to be done in memory.
SimpleDB also doesn't support the notion of cross-domain joins, so you can't query for items in multiple domains.
SimpleDB 也不支持跨域联接的概念,因此您不能查询多个域中的项目。
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After China joins WTO, the enterprises in his west hill face the challenges from the enterprises at the developed area and the cross nation ones as well.