Does Automatic Rollback Occur When a COMMIT TRANSACTION is Absent?

Automatic Rollback in the Absence of COMMIT TRANSACTION

When executing a series of SQL statements within a transaction, the intent is for all changes to be applied atomically or not at all. In situations where a subsequent statement encounters an error, the question arises whether the transaction is automatically rolled back without an explicit ROLLBACK TRANSACTION command.

Consider the following example:

START TRANSACTION;

BEGIN;

INSERT INTO prp_property1 (module_name,environment_name,NAME,VALUE) VALUES ('','production','','300000');

/** Assume that a syntax error occurs here...**/
Blah blah blah

DELETE FROM prp_property1 WHERE environment_name = 'production';

COMMIT TRANSACTION;

The misconception is that the transaction is automatically rolled back as soon as an error occurs.

However, this is not the typical behavior of database systems. In the absence of a client-enforced policy, an error does not automatically trigger a rollback. Instead, the error is reported, and the transaction remains open, allowing the user to take appropriate actions.

In the provided example, if a syntax error were encountered, the insert statement would fail, but the transaction would not be rolled back. The DELETE statement would still be executed, and the data would be deleted from the table.

This behavior can be controlled by the client or application that is executing the transaction. Some client-side tools or frameworks may implement a policy where an unhandled error triggers a rollback. However, it's important to remember that this is not the default behavior in database systems and should not be relied upon.

To ensure that the transaction is rolled back if an error occurs, it's essential to use error handling or explicitly issue a ROLLBACK TRANSACTION command in the event of an error.

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