A star join query typically involves a fact table and several dimension tables, with join predicates between the fact table and each dimension table.
一个星型连接查询通常包含一个事实表和几个维度表,事实表和每个维度表之间都有连接谓词。
We have already covered fact and dimension tables, so in this column, we will look at how to design summary tables.
我们已经讨论过事实表和维度表,因此本专栏将关注如何设计汇总表。
If the query was written by adding a dimension followed by a fact and then another dimension, then the database optimization would include the materialization as necessary.
如果查询的创建是通过先添加维度再添加事实表然后又添加维度的方式构成,那么数据库优化则必须包含实体化。
In fact, I'm going to use only two dimensions for most of the time because the difference between one dimension and two is very great.
实际上,大多数时候我只考虑二维的情况,因为一维和二维的差别很大
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