What methods can be used to implement transactional data processing in SQL?

Transactional data processing in SQL can be implemented using the following methods:

1. Explicit transaction management using commands like BEGIN TRANSACTION, COMMIT, and ROLLBACK. This allows explicitly starting a transaction, committing changes, or rolling back in case of an error.

2. Automatic transaction management through isolation level settings and autocommit. For example, in JDBC, you can disable autocommit and manage transactions programmatically.

3. Using transaction APIs in Java, for example, through Connection:

connection.setAutoCommit(false);
try {
    // Execute SQL operations
    connection.commit();
} catch (SQLException e) {
    connection.rollback();
}

4. Database-level transactions, where the DBMS itself ensures atomicity and consistency of operations.

Thus, transactions ensure data integrity by allowing multiple operations to be grouped into a single logical action.