The back-end tier is responsible for persisting and manipulating data.

后端这一层负责保存和操作数据。

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The data repository tier, or back-end tier, comprises all of the model artifacts and the full structure of the models, which handle integrated business data from all required data sources.

数据存储库层，或后端层包含了所有的人工模型组件和完整的模型结构，它们处理所有必要数据源中的集成业务数据。

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The Web tier is generally driven by end users performing business tasks, so it's better equipped to handle business-level exceptions.

We b层通常是由执行业务任务的最终用户驱动的，所以最好用它处理业务级异常。

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Texas Memory (a private company) has provided high end Tier 0 DRAM and more recently Tier 0 and Tier 1 NAND flash-based storage systems since 1978.

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While the game may end with a tier 3 monster or two landing down, the many plays leading up to that are what decide the game.

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As Vita delivers the long promised reality of console gaming on the go, it signals the end of second-tier portable versions of big franchises.

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