by Dinesh Thakur Category: Servlet with MySql Database

When a database is updated with each Statement object, by default, it will automatically commit the changes (permanently) to the database immediately. In general, to complete a transaction, it is required that one or more statements be executed. Thus, there are situations where a commit statement is needed after execution of more than one statement. In Java, the Connection object performs transaction control. The Connection object provides a method setAutoCommit (boolean value) to specify whether a transaction (or a set of transactions) should commit automatically or manually. By default, it is set to auto-commit mode. The syntax for this is the following:

dbcon.setAutoCommit (true);

This auto-commit feature can be turned off with the statement:

dbcon.setAutoCommit (false);

To commit a transaction, when the auto-commit feature is off, the statement to be used is the following:

dbcon.commit ();

If a transaction is to be rolled back at any point, this can be specified as follows:

dbcon.rollback ();

In general, the rollback statement is used in exception handlers to recover from errors that may have occurred during execution of a transaction.

 

                                           Table Methods of the class SQLException.

Name of method

Description

public int getErrorCode ()

Returns the integer value containing the vendor-specific code.

public SQLException getNextException ()

Returns the next exception in the exception

chain.

public String getSQLState ()

Returns the string containing the SQL state.

The version JDBC 3.0 API allows the programmer to create save points to be specified during a transaction, after which a rollback may be issued: this transaction can rollback the changes that have taken place after the save point.





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