A Cognos report is only as good as its data. How that data is organized will affect performance, accuracy, and ease of authoring. There is no single solution — before you get can your data right, you need to know how it is going to be used.
Know Your Requirements
In an ideal world, databases would produce the data for any kind of report with equal speed and ease. Unfortunately, this is not the case. Business Intelligence queries, in particular, frequently push the envelope of what databases can be expected to deliver. In order to keep performance acceptable, design compromises need to be made. Usually, this means making certain types of queries faster at the cost of making all other queries slower. If the faster queries are the ones the users care about, then the compromise will be a success. Read more