MySQL uses the procedure analyze() function to optimize the table structure-Mysql Tutorial-php.cn

MySQL uses the procedure analyze() function to optimize the table structure

黄舟

Release： 2017-01-18 11:15:06

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Mysql relational database management system

MySQL is an open source small relational database management system developed by the Swedish MySQL AB company. MySQL is widely used in small and medium-sized websites on the Internet. Due to its small size, fast speed, low total cost of ownership, and especially the characteristics of open source, many small and medium-sized websites choose MySQL as their website database in order to reduce the total cost of website ownership.

I don’t know if you have ever been depressed about what type of fields to choose for the MySQL table structure? Or are you confused about what length to choose for a MySQL field? In the following article, I will introduce to you a martial arts secret that I only learned recently. Friends who are interested can take a look below.

Introduction

The procedure analyze() function is MySQL’s built-in field type that performs statistical analysis on MySQL field values and gives suggestions.

Syntax

procesure analyse(max_elements,max_memory)

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max_elements

Specifies the maximum value of non-duplicate values in each column. When this value is exceeded, MySQL will not recommend the enum type.

max_memory

analyse() finds the maximum memory size used for all distinct values for each column.

Practical Exercise

# 对t1表所有的列进行分析
wing@3306>show create table t1;
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                   |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------+
| t1  | CREATE TABLE `t1` (
 `id` int(11) DEFAULT NULL,
 `name` varchar(16) DEFAULT NULL,
 `score` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+-------+--------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
wing@3306>select * from t1 procedure analyse(4);
+---------------+-----------+-----------+------------+------------+------------------+-------+-------------------------+-------------+---------------------------+
| Field_name | Min_value | Max_value | Min_length | Max_length | Empties_or_zeros | Nulls | Avg_value_or_avg_length | Std | Optimal_fieldtype |
+---------------+-----------+-----------+------------+------------+------------------+-------+-------------------------+-------------+---------------------------+
| wing.t1.id  | 1    | 200000  |    1 |    6 |     0 |   0 | 100000.5000  | 116099.2790 | MEDIUMINT(6) UNSIGNED NOT NULL |
| wing.t1.name | 000jxc6V | zzznmkcX |     8 |     8 |      0 |   0 | 8.0000  | NULL    | CHAR(8) NOT NULL     |
| wing.t1.score | 1   | 100  |  1 | 3 |  0 |   0 | 50.4889  | 28.8768 | TINYINT(3) UNSIGNED NOT NULL  |
+---------------+-----------+-----------+------------+------------+------------------+-------+-------------------------+-------------+---------------------------+
3 rows in set (0.14 sec)

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Summary

The above is all about the procedure analyze() function in MySQL. For more related content, please pay attention to the PHP Chinese website ( www.php.cn)!