1. fact table
   1. measures
      1. measures for sales fact table
         1. Topic
      2. 也叫business facts
   2. dimension table
   3. sample
      1. a sample for the sales fact table
         1. Topic
2. Star Schema
   1. multi-dimension database
   2. most common model for OLAP
3. snowflake(雪花型)
   1. 一般不用，节省的是维度表的空间，不值
4. fact constellations（星座）
   1. 由一组星型模型构成
   2. 多事实表共享纬度表
   3. sample
      1. Topic
5. DMQL
   1. define cube
   2. define dimension