Data Warehouses: Next Generation vs. Legacy
Legacy Data Warehouse
Here at the UMN we have had a set of reporting and analysis data structures in production for many years. OIT developed a set of topics (called Subject Areas), each with a set of specific tables that contain data related to that topic.
These “legacy” tables hold data from several systems, but most are drawn from the PeopleSoft systems. They are built using terminology that is most commonly found in the PeopleSoft operational world. In fact, all the tables are prefixed with PS_ to indicate the data was sourced from one of those systems.
The Legacy data tables were designed much like spreadsheets having many columns for each row. These flat structures let users get most of the data they need without having to “join” two or more tables together. For a listing of the Subject areas, their tables and descriptions go to dw.umn.edu
To get access to the Legacy Data Warehouse requires filling out the appropriate Access Request Form (ARF) to get an account with permissions to the requested Subject Areas tables. For an overview of the ARF process see the link to the Access Request site.
When connecting to the Legacy data warehouse, use the standard TNSNAMES entry DWEPRD.WORLD to point your BI tool or SQL query tool to this data set.
Next Generation Enterprise Data Warehouse
The flat, single table approach use in the Legacy Data Warehouse is an older design which does not take advantage of newer “dimensional modeling” techniques. To provide a more flexible and scalable platform that uses a more modern design, OIT is working together with Enterprise Data Management and Reporting and data experts from across the University to build the Next Generation Enterprise data warehouse.
This newer warehouse contains data in the Fact and Dimension format which allows more combinations of complex data and enables more diverse questions to be answered. By defining reusable Dimensions with a variety of Fact tables the new Next Generation Enterprise enables a more flexible and scalable analytical data store.
Access to the new Next Generation Enterprise data warehouse is provided via UM Analytics Business Intelligence tools, most notably the Oracle Business Intelligence Enterprise Edition (OBIEE). This comprehensive BI platform provides access control, navigation, reports and dashboards capabilities.
The new Next Generation Enterprise data warehouse is currently only providing access via UM Analytics.
When to use Legacy vs Enterprise Data Warehouse
Since the Next Generation Enterprise data warehouse is still a work in progress, it does not have all the data currently in the Legacy data warehouse. Therefore, it is necessary to choose which database to use based on the data available and your needs. Eventually, most of the data in the Legacy data warehouse will be migrated to the EDW.
You can find more information on the service details page for the Legacy Data Warehouse
You can find more information on the service details page for the Enterprise Data Warehouse