Saving history for the dimensional data

In the previous chapter, we saved the history of our first table, which was about positions. That is a FACT table, as it records information about facts that have happened or the state of a system at some point in time.

Facts may be subject to change. If they are, we need a business key to recognize the different instances of the fact, as we did for the positions. Alternatively, facts may be immutable, and then we do not need a business key, as is the case with web views.

Now we are going to save the history of our first DIMENSION.

Dimensions store descriptive information that allows us to fully comprehend a fact, such as information about a customer or, in our case, about securities.

The entities described by dimensions are long lived, often referenced by multiple facts at different times, and can generally change during their lifetime. Because of this, correctly defining the identity of the entity, hopefully with a business key...