Are data modification operations automatically submitted in MySQL?

Data modification operations in MySQL are automatically submitted by default, that is, every time an UPDATE, INSERT, DELETE, etc. data modification operation is performed, it will take effect immediately and be submitted to the database. The advantage of this is to ensure data consistency and durability, but sometimes it also brings certain risks. For example, when performing multiple modification operations, you may want to submit all operations at once instead of submitting each operation immediately.

MySQL provides the concept of transactions, which can manually control the submission of data modification operations, thereby enabling multiple operations to be submitted at one time or rolled back.

Below I will use specific code examples to demonstrate the automatic submission feature of data modification operations in MySQL and how to manually control submission.

First, we create a table named "test_table" with the following structure:

CREATE TABLE test_table (
    id INT PRIMARY KEY,
    name VARCHAR(50)
);

Next, we insert some test data:

INSERT INTO test_table (id, name) VALUES (1, 'Alice');
INSERT INTO test_table (id, name) VALUES (2, 'Bob');
INSERT INTO test_table (id, name) VALUES (3, 'Charlie');

Now we try to execute a simple UPDATE statement to modify the data and see the effect of automatic submission:

UPDATE test_table SET name = 'David' WHERE id = 1;
SELECT * FROM test_table;

After executing the above statement, you can see that the data has been successfully modified, indicating that the modification operation was automatically submitted.

Next, we manually control the submission of data modification operations by setting up transactions:

START TRANSACTION;
UPDATE test_table SET name = 'Eve' WHERE id = 2;

Here, we use START TRANSACTION to start a transaction and temporarily not commit after the operation of updating the data.

Then we try to query the data. At this time, the modification has not been submitted, so the query will still return the previous data:

SELECT * FROM test_table;

Then we submit this manually Transaction:

COMMIT;

After executing the above statement, query the data again and find that the data has been successfully modified.

In addition, if you want to undo the previous modification operation and roll back the transaction, you can use the ROLLBACK command:

START TRANSACTION;
UPDATE test_table SET name = 'Grace' WHERE id = 3;
SELECT * FROM test_table;
ROLLBACK;
SELECT * FROM test_table;

In the above example, after executing ROLLBACK, it is found that the data has not been modified, indicating that the transaction has been successfully rolled back.

Through the above example, we can see that data modification operations are automatically committed by default in MySQL, but the commit or rollback operation can be manually controlled through transactions to achieve a more flexible data operation method.

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