What are the models of data modeling

---

1. Star model

   Star model is the most commonly used dimension modeling method . The star model is centered on the fact table , All dimension tables are directly connected to the fact table . The star model consists of a fact table and a set of dimension tables .

2. Snowflake model

Snowflake mode (Snowflake Schema) It's an extension of star mode . The dimension table in snowflake mode can have the , Although this model is more standard than star , But because this model is not easy to understand , Maintenance costs are high , Moreover, the performance aspect needs to associate multi-level dimension tables , The performance is lower than that of star model .

3. Constellation model

Constellation pattern is an extension of star pattern , The star pattern is based on a fact table , And the constellation pattern is based on multiple fact tables , And share dimensional information . In many cases, there is more than one fact table in the dimension space , A dimension table can also be used by multiple fact tables . In the late stage of business development , The vast majority of dimensional modeling uses constellation mode .