How to modify the default value of a field in mysql

MySQL is an open source relational database management system that is widely used in various enterprises around the world. When using MySQL, you often need to modify the default value of a field in a table in the database. This article will introduce in detail how to modify the default value of a field in a table in MySQL.

1. Use the ALTER TABLE statement to modify the default value

The ALTER TABLE statement is one of the common statements used to modify the table structure in MySQL. It can be used to add, delete, and modify tables. fields, and modify table constraints and other operations. To use the ALTER TABLE statement to modify the default value of a field in a table, you need to follow the following steps:

Step 1: Open the MySQL command line tool

Enter the following command on the command line:

$ mysql -u root -p

Then enter the correct password to log in.

Step 2: Select the database to be modified

In the MySQL command line tool, enter the following command to select the database to be operated:

mysql> use dbname;

Among them, dbname is the database you want to modify. Modify the database name of the field's default value, making sure to replace it with the actual database name.

Step 3: Execute ALTER TABLE statement

Execute the following ALTER TABLE statement to modify the default value of a field in the specified table:

mysql> ALTER TABLE table_name ALTER COLUMN column_name SET DEFAULT default_value;

Among them, table_name is to be modified The name of the table; column_name is the name of the column whose default value is to be modified; default_value is the new default value.

After executing the above command, MySQL will modify the default value of the specified field in the specified table to the new default value.

2. Use PHPMyAdmin to modify the default value

PHPMyAdmin is a well-known MySQL database management tool, which can be used to easily manage and maintain MySQL databases, including Create, modify, delete tables and fields, etc.

To use PHPMyAdmin to modify the default value of a field in a table in MySQL, you need to follow the following steps:

Step 1: Open PHPMyAdmin

Start the browser and enter http: //localhost/phpmyadmin/Enter the PHPMyAdmin management page and select the database that needs to be modified.

Step 2: Select the table and open the "Structure" tab

In the PHPMyAdmin interface, select the table that needs to be modified and open the "Structure" tab.

Step 3: Select the field to be modified

In the "Structure" tab, select the field whose default value you want to modify, and click the "Modify" button.

Step 4: Modify the default value

On the "Modify Field" page, find the default value setting option and enter the new default value. Then click the "Save" button to save the changes.

The advantage of using PHPMyAdmin to modify the default value of a field in a table in MySQL is that the operation can be completed through a graphical interface without the need to enter complex SQL statements, making the operation simple and convenient.

Summary

Modifying the default value of a field in a table in MySQL is one of the operations that is often required in MySQL database management. This can be accomplished using both the ALTER TABLE statement and the PHPMyAdmin tool. The ALTER TABLE statement needs to be used under the MySQL command line, which is suitable for users who are familiar with MySQL syntax; the PHPMyAdmin tool completes operations through a graphical interface, which is more convenient and simple for users who are not familiar with MySQL syntax.

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