CIS 4400 Lecture Notes - Lecture 5: Data Warehouse, Snowflake Schema, Fact Table
- how many orders were placed and fulfilled per month? (ask for month and year) Select to_char (o. orderdate, yyyy-mm") as order_month, count(*) as. You are lagging 1 month behind and lagging it over this. Lag( count(*), 1, 0) over (order by to_char(o. orderdate, yyyy-mm")) as prior_order_count. - how to subtract the two months from each other. Says you start off with one function and then get one dimensional model. Then you go to another function of the business, isolate it, and create a data mart. Separate olap systems at first and then you combine them into an enterprise data warehouse: drill across: share some dimensions when creating the enterprise data warehouse. Don"t care about the business functions needed for requirements gathering. How do we integrate something that already works together: key performance indicator (kpi): a calculation that is important to the organization. Can sometimes come directly from the transaction process system or is a combo of the transactional processing system: feasibility.