Extraction of OLAP to Excel Oracle Tips by Burleson Consulting

The Data Warehouse Development Life Cycle

Online Analytical Processing and Oracle

Using Excel Pivot Tables For OLAP

The Microsoft Excel spreadsheet product is an excellent way to demonstrate the capabilities of an OLAP application. Many companies extract de-normalized information from their Oracle databases, FTP the data to a PC LAN, and load the file into a very large Excel spreadsheet on a client PC (see Figure 5.2). The manager can then use Excel’s Pivot table wizard to analyze the data, just as if they were using a multidimensional database. Of course, this approach requires a very powerful PC, but it is a very fast, simple, and straightforward approach to simulating a multidimensional database with an OLAP application.

Figure 5.2 Extraction of summarized data for PC-based OLAP.

The Oracle data extraction is usually invoked from a Unix crontab task, which invokes an SQL script to extract the summarized data from Oracle, format the data, and pipe it to a flat file. Using NFS, a mount on a PC LAN can be created so that the extracted data is transferred directly to the PC disk. The data can then be easily loaded into a spreadsheet, where the wizard will allow the manager to perform complex cross-tabulations and decision support queries.

Note: To get the maximum benefit from this exercise, I recommend that you follow along on your PC. Simply start Microsoft Excel, and load the file called pivot.xls from the CD-ROM in the back of this book. This short exercise will only take about ten minutes, and it has proven of be the best method for understanding multidimensional databases.

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This is an excerpt from "High Performance Data Warehousing", copyright 1997.

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