jodd-db/src/main/java/jodd/db/DbSession.java
protected void openTx() {
		if (connection == null) {
			connection = connectionProvider.getConnection();
		}
		txActive = true;
		try {
			connection.setAutoCommit(false);
			if (txMode.getIsolation() != DbTransactionMode.ISOLATION_DEFAULT) {
				connection.setTransactionIsolation(txMode.getIsolation());
			}
			connection.setReadOnly(txMode.isReadOnly());
		} catch (SQLException sex) {
			throw new DbSqlException("Open TX failed", sex);
		}
	}
protected void openTx() {
		if (connection == null) {
			connection = connectionProvider.getConnection();
		}
		txActive = true;
		try {
			connection.setAutoCommit(false);
			if (txMode.getIsolation() != DbTransactionMode.ISOLATION_DEFAULT) {
				connection.setTransactionIsolation(txMode.getIsolation());
			}
			connection.setReadOnly(txMode.isReadOnly());
		} catch (SQLException sex) {
			throw new DbSqlException("Open TX failed", sex);
		}
	}
Opens a transaction.