Transaction API #3

// Flat interface.
var trx = db.begin();
trx.on('commit', function() {});
trx.on('rollback', function() {});


trx.rollback();
trx.commit(); // No implicit commit when calling db.begin();

// Creates a new stack
db.transaction(function(trx) {
    trx == this
    // implicit begin

    // transaction objects are like database objects:

    trx.run("CREATE TABLE foo (id INT PRIMARY KEY, bar)");
    trx.run("INSERT INTO foo VALUES(?, ?)", 1, "first text");
    trx.run("INSERT INTO foo VALUES(?, ?)", 1, "second text"); // will fail
    trx.run("INSERT INTO foo VALUES(?, ?)", 1, "third text", function(err) {
        if (err) {
            // Do nothing and the error will be ignored

            // See below for more explanation
            trx.clear();
            trx.rollback();
            trx.commit();
        }
    });

    trx.on('rollback', function() {
        // This is emitted after the transaction was rolled back.
    });

    trx.on('commit', function() {
        // This is emitted after the transaction was committed successfully.
    });

    trx.on('error', function() {
        // This will be called when a statement execution doesn't have a callback
        // and no error handlers.

        // removes all further statements from the stack. You can now add more
        // statements to the stack. the automatic commit on empty stack persists.
        // Does not remove the error handler, you have to do that manually.
        trx.clear();

        // removes all further statements from the stack and does a rollback of the
        // entire transaction.
        trx.rollback();

        // removes all further statements from the stack and commits the transaction
        trx.commit();
    });

    // when no error handler is attached and an error bubbles up to the transaction's
    // error event, the transaction is rolled back and the rollback event is emitted.

    // implicit commit when the stack is empty.
});