Shulou(Shulou.com)05/31 Report--

This article mainly introduces "what are the common problems of MySQL". In daily operation, I believe many people have doubts about the common problems of MySQL. The editor consulted all kinds of materials and sorted out simple and easy-to-use methods of operation. I hope it will be helpful for you to answer the questions of "what are the common questions of MySQL?" Next, please follow the editor to study!

1. A table with a self-increasing primary key of ID. When insert has 17 records, delete the 15th insert, then restart the Mysql, and then insert a record. Is the ID of this record 18 or 15?

(1) if the type of the table is MyISAM, it is 18 because the MyISAM table records the maximum ID of the self-increasing primary key in the data file, and the maximum ID of restarting the MySQL self-increasing primary key will not be lost.

(2) if the type of the table is InnoDB, then the 15InnoDB table only records the maximum ID of the self-increasing primary key in memory, so restarting the database or performing OPTIMIZE operations on the table will cause the maximum ID loss.

2. What are the technical characteristics of Mysql?

Mysql database software is a client or server system, which includes multithreaded SQL servers supporting various client programs and libraries, different backends, a wide range of application programming interfaces and management tools.

3. What is the Heap table?

The HEAP table exists in memory and is used for temporary high-speed storage.

BLOB or TEXT fields are not allowed

You can only use the comparison operator =, = >, =

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