The operation of modifying the table structure in phpMyAdmin mainly includes the following steps: 1. Enter the "Structure" page of the target database and table; 2. Click the "Change" button of the field to edit; 3. Modify the field name, type, length, and whether it is allowed to be empty; 4. Adjust the field order or add new fields; 5. Confirm data compatibility and application layer logic before saving. When modifying, special attention should be paid to the compatibility of primary keys, index fields and existing data to avoid index failure or data loss. It is recommended to back up data before operation.

Modifying the table structure in phpMyAdmin mainly adjusts the field's name, type, length, and whether it is allowed to be empty. This operation is not complicated, but requires careful processing, especially online databases, which may cause data exceptions if they are corrected.

Enter the table structure editing interface

To modify the table structure, you must first find the corresponding database and table. Click the database in the navigation bar on the left, and then click the table name you want to modify. Then there will be a "Structure" tab at the top menu bar. Click in to see all the field information of the current table.

On this page, each field has a "Change" button (usually displayed as a pencil icon), clicking it to enter the field editing page. At this time, you will see various settings for the field, including type, length/value, default value, whether NULL is allowed, primary key settings, etc.

Modify field name and type

If you just want to change the field name or type, just modify it in the corresponding input box. For example, change username user_name , or change VARCHAR(50) to VARCHAR(100) .

What should be noted is:

• If the field is a primary key or has an index, be careful when changing the type. Some type conversions may cause the index to fail.
• If there is data in the field, it can be changed to an incompatible type (for example, from VARCHAR to INT ), data loss or error may occur.
• After modifying the length, you should also consider whether the actual data exceeds the new limit, otherwise an error will be prompted when saving.

For example: You originally had a field that was age VARCHAR(2) , but now you want to change it to INT type, so there is no problem. But if there is a string like 'twenty' , it will cause an error or even fail if it is converted to INT.

Adjust the field order and add new fields

phpMyAdmin also supports adjusting the position of fields. On the field editing page, there is a drop-down menu for "Put fields after this field" below. You can choose which field you want it to appear after. This allows you to organize the table structure flexibly.

If you want to add a new field, you can click "Insert at the end" or the "" next to a field on the structure page to add a new column. When adding, you need to fill in the field name, type, length, whether empty values ??are allowed, etc. After filling, click the execution and complete it.

Sometimes we encounter such a need: for example, there was no mobile number field in the user table, but it was added later. At this time, you can quickly add this function.

Basically these are the operations. Modifying the table structure seems simple, but in a formal environment, it is recommended to back up the data first, especially when it involves field type conversion or renaming, be sure to confirm whether the application layer logic depends on the old field name or format.

The above is the detailed content of How to modify table structure in phpMyAdmin? Adjust fields and types. For more information, please follow other related articles on the PHP Chinese website!