If you have invoked a database, you have the necessary privileges
    to use the START_TRANSACTION statement.

    If you issue a data manipulation statement without issuing START_
    TRANSACTION first, Oracle Rdb automatically starts a transaction
    for you, using the READ_ONLY option. Thus, you can perform simple
    data retrieval without starting a transaction explicitly.

    If you issue a data manipulation statement, such as GET or PRINT,
    and then try to use START_TRANSACTION, you may get an error
    message warning you that a transaction is already in progress.
    To solve this problem, always issue an explicit START_TRANSACTION
    statement when you plan to perform more than one operation.

    You must have the DISTRIBTRAN database access right to a database
    to run a two-phase commit transaction on that database.