但是最简单的数据库并不要求使用所有允许的类型，通常只需要保存数值型、字符型和日期(或时间)数据。

But most simple databases don't require the full range of allowed types, and often they need to store only numerical, character, and date or time data.

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对数值型数据保持顺序加密方法进行了分析，在此基础上提出了一种在关系数据库中针对字符数据的保序加密方法。

In this paper the order preserving encryption for numeric data is analyzed. An order preserving encryption method for character data in relational databases is proposed.

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提出一种关系数据库水印算法，适用于数值型数据的版权保护。

An algorithm for relational database watermarking is proposed in this paper, and it is applicable to protect the copyright of numeric data.

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