Database terminology

Interval, a database term, any continuous block allocated to an object (such as a table) is called an interval; Interval is also called extension.

Any continuous block allocated to an object (such as a table) is called an interval; Interval is also called extension, because when it runs out of allocated intervals, it needs to allocate new intervals when inserting new records (that is, expand some blocks); Once an interval is assigned to one object (table, index and cluster), it cannot be assigned to other objects.

Mathematical concept

In mathematics, an interval usually refers to a set of real numbers: if X and Y are two numbers in a set, then any number between X and Y also belongs to the set. For example, a set consisting of real numbers that conform to 0≤x≤ 1 is an interval, which includes 0, 1 and all real numbers between 0 and 1. Other examples are: real number set, negative real number set, etc.

Interval plays an important role in integral theory, because as the simplest set of real numbers, they can be easily defined as "length" or "measure". Then, we can extend the concept of "measure" and introduce Borel measure and Lebesgue measure.

Interval is also the core concept of interval arithmetic. Interval arithmetic is a numerical analysis method used to calculate rounding error.

The concept of interval can also be extended to any subset S of totally ordered set T, so that if both X and Y belong to S, and X