Flatten out a parent-child hierarchy
Where possible, you should strive for simpler models. When your report builders see fewer tables, they will be able to use the model more effectively. The simpler the model, the fewer problems you will have with it. We are not saying leave out important data, but we are saying, again, if it's not necessary, don't include it.
The most common way to do this is by using a star schema.
Star schema
A star schema organizes your data into fact and dimension tables. You can use dimension tables to filter the fact table. Dimension tables contain information that is repeated over and over again, for example, in the Sales table. If you think of a product dimension, it can hold all the information about a product, such as the name, color, SKU, size, and weight. Instead of repeating that information over and over, you can represent the product by an SKU number or even an integer in the Sales table. You can then filter the Sales table by selecting...