In the preceding section, Data modeling, we learned about the star schema, which includes one fact table and multiple dimension tables. But in the real word, there are situations when we need multiple fact tables in the data model. In such a situation, we can use two options to link them together. One is by using concatenation, and the other is by using the link table. If the granularity of the fact table is similar, we can use the option of concatenation, but if the granularity is not the same, we should use the link table option.
The link table concept requires three things:
- You need to create a composite key in each fact table
- You need to create a link table (which has common fields from both the fact table and composite key)
- If you have created the link table using resident load, you should delete the fields from the resident table that you have loaded in the link...
