指定属性类型和基数：指定一个属性的几个特征，然后为所有属性重复该步骤。
Specify attribute types and cardinality: Specify several properties of one attribute, and then repeat that step for all attributes.
这样重复地重新初始化基数值要求用户持续超出空间移位值以增加检测到的总偏差。
This repeated reinitialization of the base values will require the user to continuously exceed the dimensional shift values to increment the total deviation detected.
重复上面的步骤，再次解释查询，生成查询访问计划之后，优化器会计算出一个更好的、与实际结果很接近的基数估计值。
After repeating the above steps to explain the query again to generate the query access plan, the optimizer computes a better cardinality estimate that is very close to the actual result.
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