How to modify and add fields when MySQL table data is large

Mysql How to modify and add fields when the table data is large

This article mainly introduces Mysql How to modify and add fields when the table data is large , The content is detailed and easy to understand , The operation is simple and fast , It has certain reference value , I believe that after reading this article Mysql When the table data is relatively large, you will gain some experience in how to modify and add fields , Let's have a look .

Preface

If a table is in later maintenance , Find that you need to add fields to meet the current needs , But the amount of data is huge, there are millions or even tens of millions of data , How to modify table fields .

Directly execute using alter The statement is certainly unrealistic , This involves operations such as locking the table and reconstructing the table structure , Suppose there are other threads running at this time , I can't change it for a day .

Here is a simple way to sort out

1、 Create a temporary table against the table structure to be operated

CREATE TABLE product_copy LIKE product;

2、 Change the table structure to be modified to the temporary table

3、 Export table product data , And import to the zero hour table product_copy

4、 Use RENAME Statement replacement table name

RENAME TABLE product TO product_bak, product_copy TO product;

But when the amount of data is too large , Exporting and importing also takes some time , And the data is error prone , It is recommended to use datagrip Import and export tools for , perhaps idea Data source plug-in for , Best use csv File to import and export .

1、 Right click the table name and select import data

2、 In the import interface, you can clearly see the corresponding relationship of fields , If there is a problem, you can adjust it directly , What you see is what you get

3、 If the header is displayed when exporting , You can also right-click the first row to mark it as a header , It is more convenient to see the corresponding data

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