What does desc mean in mysql?

In MySQL, the DESC command is used to describe the table structure. It displays information about the table or view column by column, including field names, data types, whether null values ​​are allowed, default values, and key constraints. It helps determine the type of data stored in a table, find primary key and foreign key constraints, and understand the overall layout and relationships of the table.

The meaning of DESC in MySQL

In the MySQL database, the DESC command is used Describes the structure of a database table or view. It displays column-by-column information about a table or view in a readable form.

Syntax

<code>DESC <表名|视图名>;</code>

Output content

DESC The output of the command usually contains the following information:

• Field name
• Data type
• Allowed values ​​(if applicable)
• Whether null values ​​are allowed
• Default value ( If applicable)
• Key constraints (primary key, foreign key, etc.)

Usage

DESC The command is database An important tool for administrators and developers to understand the structure of a table or view. It helps:

• Determine the type of data stored in the table
• Find primary key and foreign key constraints
• View settings for missing or default values
• Understand the overall layout and relationships of the table

Example

To view the structure of the customers table, you can use the following command:

<code>DESC customers;</code>

The output will display the following information:

<code>Field       Type        Null    Key     Default  Extra
id          int(11)     NO      PRI     NULL    auto_increment
name        varchar(255) YES     MUL     NULL    
email       varchar(255) YES     MUL     NULL    
phone_number varchar(20)  YES     MUL     NULL    </code>

This indicates that the customers table has four fields: id, name , email and phone_number. The id field is the primary key, and the name, email, and phone_number fields allow null values. The id field uses the auto_increment attribute, which means that newly inserted rows will automatically be assigned an incrementing integer as the id value.

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