You can also join customers and orders in a query by forming the cross-product and retrieving all the relative bits of data as one large projection.
您还可以在查询中联接客户和订单,方法是构建叉积并将所有相关数据位作为一个大型投影检索出来。
Building bitmap join indexes of dimension tables and fact tables directly may bring a large number of useless index items that affect query efficiency.
直接建立维度表与事实表的位图连接索引会产生大量无用的索引项,影响查询效率。
Query optimization for large join queries is one of the key factors to improving the performance of database systems.
多连接查询优化是提高数据库性能的关键问题之一。
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