As we have all seen there has been significant consolidation with in the BI tool space in the past 18 months or so. Some of the bigger players have been (or soon will be) assimilated into the other vendors’ product portfolios. In the main it has been the database vendors

Sometimes people write to me or post questions on the blog along the lines of "I'm new to data warehouses, which xxxx is best?" where xxxx could be tool, database, hardware platform, design methodology, in fact, xxxx could be almost anything. Well, nothing is clear-cut, the

One of the themes I keep retuning to is the time dimension in Data Warehouses. I use the word "time" in the physics sense of something continuous and not the cyclical "clock" sense. Time (and in my sense, time could be measured in units far more

Recently the Economist Intelligence Unit published a paper (jointly sponsored by Intel and SAP) entitled "Business Intelligence: Putting information to work [http://www.eiu.com/Business_intelligence]" The key findings here echo those my company has found in it its own research and vendor views given in partner

In a way, this is the second part of a piece on non-reporting [https://www.rittmanmead.com/blog/2006/09/05/moving-from-tradition/] tool BI. Consider a customer contact centre - historically the realm of CRM applications. Customers interact with agents by voice telephony, text messaging, email, web portals, in writing,

Re-summarization, re-statement or re-summarisation, call it (or spell it) as you will, is a periodic maintenance task in some data warehouses. Most fact tables contain just the measures and keys to the dimension tables. This design is flexible in that it supports both non-changing and slowly changing dimensions, and for

The last DW post talked about dates and times within a data warehouse. The time that a sale or some other transaction occurs can usually be recorded by an Oracle DATE value in the data warehouse; some DW may need to use timestamps, but to-the-second times would normally be adequate.

For most data warehouses the time (date) dimension appears, or at least should appear, in every query. I can think of a few DWs where time is not always used; one example being an asset (infrastructure) maintenance reporting system for a utility company, each pipe, inspection chamber, valve, or whatever

Yesterday [https://www.rittmanmead.com/blog/2006/02/16/what%e2%80%99s-that-about-then/] I had a small rant about the use of case statements in where clauses. In a reply to this parkerpg suggested this was perhaps generated by the use of query environment such as Cognos. In this case

At the risk of Tom Kyte telling me that I have given up thinking… Any ideas why this appeared as part of a WHERE predicate (or more to the point why write it!) > … AND ( case when T.V_STATUS = 'A' then 'Active' when T.V_

Recently we implemented some changes on a customer’s DW to improve query performance. As usual, all changes were fully tested before implementation on the production system, but because of the nature of the changes and the fact that it is difficult to adequately emulate user workload we also adopted

In most data warehouses there is some form of aggregation going on, sometimes in the presentation of database summary tables, sometimes in the query tool. Often this aggregation is additive over time: how many times did this IP address connect to that web page in a month, what is the

In follow-ups to recent [https://www.rittmanmead.com/blog/2005/08/31/know-who-your-customers-are-%e2%80%93-part-1/] posts [https://www.rittmanmead.com/blog/2005/09/05/know-who-your-customers-are-%e2%80%93-part-2/] some people raised a point about using basket analysis in “reverse” to segment customers. The legend that young men buy beer