I have a question about OLAP. OLAP is very popular recently. Before when we were talking about BI, we wanted to know our company's economic benefit, customers, orders, etc., we used MIS reports. Now, why do we need OLAP if we have already have so many reports. What is the difference between an MIS report (or EIS reports) and an OLAP cube?


Les Barbusinski’s Answer: Fundamentally, the difference between “flat” operational reports and OLAP reports is that the latter operates from a dimensional model of the business. So-called flat reports tend to be lists of entities and/or transactions, while OLAP reports tend to measure some aspect of the business against one or more dimensions (such as time, products, organizations, geographic areas, etc.). Since dimensions tend to be hierarchical (e.g., an office reports to a district, which reports to a region, which reports to a division and so on), OLAP reports have the ability to dynamically drill up, down or across those hierarchies and to slice and dice the metrics by applying filters. For example, a typical operational report might list all product orders for the prior month in descending dollar value, while a typical OLAP report would identify the top 10 products with the highest percentage increase in orders in the prior month…and would let you drill down the order volumes from the division totals to an individual store level. It might even let you dynamically drill across to see which 20 stores contributed most to the Top 10 ordered products in the prior month.

Doug Hackney’s Answer: OLAP provides the capability to interactively slice and dice or view the data by a multitude of dimensions as well as the ability to drill down through the data into the transaction detail. For instance, the OLAP user and interactively determine to view the data by customer by time by product or by customer by region by discount, etc. The real- time interactive nature of OLAP multidimensional analysis is the most powerful feature for users versus static reports.

Scott Howard’s Answer: MIS is great for generating what we call "flat" or two dimensional reports. Creating these reports with several levels of breaks or sub aggregates becomes difficult to read and troublesome to code. These type of requirements also wreak havoc on your RDBMS system as they are usually very resource intensive causing performance problems and lengthy wait times for results.

OLAP is online analytical processing and usually refers to the product or architecture implemented to store and query the data (MOLAP or multidimensional OLAP and ROLAP or relational OLAP). These architectures and the products that implement them allow for multidimensional analysis to easily satisfy queries like: how many customers from the Northeast purchased an auto policy in August and September that resulted in at least a net loss. Here we have a measure, profit/loss, analyzed over product, customer, geography and time. This is done by employing such techniques as slice and dice, pivoting, drill down and roll up which are much simpler to manipulate than their would- be SQL equivalents. Their architectures also support faster retrieval than flat modeled stores because most of the aggregates and combinations of data required for such complex queries is precaculated and stored.

MIS solutions are fine for analyzing your company's economic benefit, customers, orders etc. independently. If you have complex business intelligent query needs like the one I just illustrated or would like the query to combine several of your pervious queries simultaneously, you should look at OLAP solutions.

Chuck Kelley’s Answer: OLAP encompasses many things, including MIS/EIS Reports, so the terms are not comparable from that standpoint. If all you want are MIS/EIS Reports, then generate that. OLAP also encompasses data mining, the exploration into data to find facts and trends that may not be able to be processed by a single SQL Query that is used to produce an MIS/EIS Report. I liken OLAP to fruits and MIS/EIS reports as oranges – just a subset of the major category.

Clay Rehm’s Answer: The main difference between your typical MIS/EIS report and an OLAP cube is functionality. The OLAP cube will allow the user to slice and dice data in whatever dimensions have been set up in the cube. This makes it less of a report and more of an ad hoc query environment. A well designed data warehouse will include more than one way to get to the data. This will include OLAP cubes and preformatted reports.

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