Good logical and physical design is the cornerstone of high performance, and you must design your schema for the specific queries you will run. For example, a denormalized schema can speed up some types of queries but slow down others.
Adding counter and summary tables is a great way to optimize queries, but they can be expensive to maintain.
If you need to study the basics of database design, we suggest Clare Churcher’s book (Apress).
This chapter is preparation for the two that follow.
On the other hand, it has a much smaller range of allowable values, and sometimes its special capabilities can be a handicap. My SQL supports many aliases for compatibility, such as can store values ranging from 0 to 255 instead of from −128 to 127.
The performance improvement from changing is usually small, so don’t make it a priority to find and change them on an existing schema unless you know they are causing problems.Both floating-point and column, you can specify the maximum allowed digits before and after the decimal point. My SQL 5.0 and newer pack the digits into a binary string (nine digits per four bytes).