There are various kinds of foods available in nature for human consumption. But maintain daily species only need nutrients: protein, carbohydrates, fats, minerals (also called inorganic salt, can be divided into two categories, major elements and trace elements), vitamins, dietary fibre and water 7 categories, a total of more than 40. Each has its own special physiological function and participates in the metabolism of human body. Any kind of natural food in nature cannot provide all the nutrients the human body needs, and it must be matched in proportion to each other to meet the reasonable nutritional needs of the human body. Therefore, reasonable nutrition emphasizes that the nutrients in human consumption should be complete, moderate and proportionate.
1. Foundation, is based on the structure of the part, which is building the bearing component of the ground below, it holds up all the load of the upper building, and the load and the weight to the ground. The foundation must be strong, stable and reliable.
Data implementation centralized control. In file management, the data is in a decentralized state, with different users or the same user having nothing to do with their files in different processing. The database can be used to control and manage the data, and the data model represents the organization of various data and the relation between data.