通过昵称，还可以定义引用来自多个数据源的数据的视图。

Using nicknames, you can also define a view that references data from multiple data sources.

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相反，可使用具有where子句的虚拟表，或者将连接作为数据源的视图进行定义，并在这一视图中执行规则。

Instead, use a virtual table with a WHERE clause, or define the join as a view in the data source, and execute the rule on this view.

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如果您想将定义远程视图的查询下推到数据源，那么定义远程视图的昵称会比较有用。

Defining a nickname over a remote view is useful in cases where you want to push down the query defining the remote view to the data source.

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