如果一个属性仅依赖于一个多重主键的一部分，则将该属性转移到一个单独的表中。

If an attribute depends on only part of a multi-valued key, then remove it to a separate table.

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表3：多重值和它们的表示。

Table 3: Multiplicity values and their indicators.

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然而，如果每个不同的索引值都有许多重复的行，而所关联的表是高度群集的，那么通过索引添加的连接成本可能很低。

However, if there are many duplicate rows per distinct index value, and the associated table is highly clustered, the added costs of joining through the index can be slight.

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