While creating OLAP data Warehouse solution in this NorthwindLite database example, I have created Products, Customers and Date dimension table. Since Product Category does not have very critical fields to make separate table, I merged product category fields with Product dimension table and make it one Products dimension table. Next I have created Customers dimension table where I skipped Customer Address field which is less important. Later I created FactOrders fact table where I created surrogate keys and primary keys.
I created date dimension table and also added OrderDatekey to the factorders table.
once the data warehouse plan worksheet has done I created the DWNorthwindLite Data Warehouse solution.
OLTP vs. OLAP Databases
OLTP
- Transactions such as Insert, update, delete.
- Usually a Entity-relationship model.
- Normalized database with lots of tables and not much duplicated data.
- Used for storing detailed and up to date data.
- Lots of transactions that is constantly updating.
- Data may be collected from multiple points of entry, e.g. web application, desktop application, point-of-sale.
- OLTP databases are primarily used to collect and store transaction data from a variety of inputs.
OLAP
- Mainly select queries with very little updates.
- Star or snowflake model.
- De-normalized so data is aggregated in fact and dim tables.
- Mainly used for data mining and reporting.
- Often complex queries that include aggregation.
- Needs fast response time.
- OLAP databases are primarily used for reporting and analysis of data.
- Serves the needs of analysts, managers and executive employees in planning, problem solving and decision support.
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