The indexing mechanism is used to speed up access to desired data, but it is not desirable to use it in some case. Which of the following descriptions do not require an index?
选项:
A:the columns often used for queries;
B:the columns often used for sorting and grouping;
C: the columns with unique values, such as primary key;
D:the columns updated frequently but rarely used for queries
发布时间:2024-05-23 18:50:27