how to drop index in mysql

MySQL 5-1 -- index bitsCN.com 1. MySQL has multiple rows that access tables. The most commonly used is sequential access and index access. Sequential access refers to browsing a table in one row, that is, full table scan. Disadvantage: it is very

Understanding MySQL-index and optimization summary, mysql Index Summary Preface: indexes have a crucial impact on the query speed. Understanding indexes is also the starting point for optimizing database performance. Consider the following: Assume

Mysql database index and mysql Index Today, let's talk about some of the indexes of the Mysql database. I think everyone knows what indexes can do? It is inevitable that data tables are quickly searched, especially those databases with millions of

The concept of MySQL indexingAn index is a special kind of file (an index on a InnoDB data table is an integral part of a table space), and they contain reference pointers to all records in the datasheet. More generally, the database index is like a

The so-called index is a specific MySQL field for some specific algorithm sorting, such as the two-fork tree algorithm and hashing algorithm, the hash algorithm is established by establishing the eigenvalues, and then based on the characteristics of

PrefaceBefore writing to MySQL on the table additions and deletions (query the most important), it feels like MySQL is almost finished, did not want to continue to learn the mentality, the reason may be due to other people's influence, think for

1. MySQL has multiple rows that access tables. The most commonly used rows are sequential access and index access. Sequential access refers to browsing a table in one row, that is, full table scan. Disadvantage: It is very time-consuming and

In-depth MySQL database index bitsCN.com Indexes are the main means to accelerate table content access, especially for queries involving connections to multiple tables. This is an important part of database optimization. we need to understand why

I. What is an index? Why index?Indexes are used to quickly find a row with a specific value in a column, and without using an index, MySQL must start reading the entire table from the first record until it finds the related rows, the larger the

First, Introduction1. What is an index?General application system, reading and writing ratio of about 10:1, and the insertion operation and the general update operation rarely appear performance problems, in the production environment, we encounter