The definition of differential in mathematics: from the function B=f(A), two groups of numbers A and B are obtained. In A, when dx approaches itself, the limit of the function at dx is called the differential of the function at dx, and the central idea of the differential is infinite division. Differential is the linear main part of function change. One of the basic concepts of calculus.

Increment refers to the change of the quantity maintained in the system within a certain period of time. The relationship between them can be expressed by the following two formulas: increment = inflow-outflow; Current period ending stock = last period ending stock+current period increment.

Increment is the change value of index, that is, the way and degree of numerical change. The increment itself is also a number. There are two kinds of changes in quantity: increase and decrease. When the number increases, the increment is positive; When the number decreases, the increment is negative. The more you increase or decrease, the greater the absolute value of the increment. If 3 increases to 5, the increment of 3 is+2; 3 is reduced to 1, then the increment of 3 is -2. In other words, the increment is the difference between the changed value and the original value.

Since the change of number has increased and decreased, why should the change value of number be called "increase" instead of "decrease"? Because, in human thinking, increasing the number of representatives is of positive significance; And reduce the negative and retrogressive emotional color. Therefore, people tend to choose "increase" as the prototype, and deduce the concept of "increment" from both increase and decrease. The concept of increment often appears in databases.