A crucial feature of every example in the first eight chapters of this book has gone unmentioned. Each and every dimension attribute has participated in a simple one-to-many relationship with every fact. This essential characteristic has allowed dimensions to be arranged around fact tables in the neat and powerful star configuration with which you are now familiar.
The real world, of course, is not always neat. Real-world complexity sometimes makes it impossible to model a process in this manner. This chapter explores two such challenges:
• Multi-valued dimensions occur when a fact table row may need to refer to more than one row in a dimension table.
• Multi-valued attributes occur when a dimension ...