Building a BI system: you might have forgotten about it

Building a BI system can be tricky. There is an opinion that this is quite simple: ".... this is not a full-stack development, it was just implemented and forgotten." In fact, it is not so. Such development is a complex process, which is fraught with many "pitfalls". In such a context, we can forget about the most important things. Often, initially, we simply do not take into account those aspects that directly affect the success of the final system and particular dashboards. 

Using examples, I will show how following simple rules affect the quality of the BI system. I will share secrets based on my own experience and passed "rake". How to implement what was really needed. How to lay a foundation that, in the future, will minimize system rework and bug fixes.