Example 1

    Ready a relation with defaults:

    START_TRANSACTION READ_WRITE

    This statement allows access to all the relations in the current
    database so that all users can modify records. It is equivalent
    to readying all the relations for the SHARED WRITE reserving
    option.

    Example 2

    Start a read-only transaction:

    START_TRANSACTION READ_ONLY

    This statement lets you read data from the database but not store
    or modify data. When you retrieve data, you see the state of
    the records as they existed at the time of the START_TRANSACTION
    statement. You do not see any updates to the database made after
    that time.

    Example 3

    Start a transaction with locked relations:

    The following statement lets you specify the intended action for
    each relation in the transaction.

    START_TRANSACTION READ_WRITE RESERVING
          EMPLOYEES FOR PROTECTED WRITE,
          JOBS, SALARY_HISTORY FOR SHARED READ

    Assume that this transaction updates the EMPLOYEES relation based
    on values found in two other relations, JOBS and SALARY_HISTORY:

    o  The transaction must update EMPLOYEES, so EMPLOYEES is readied
       for the PROTECTED WRITE option.

    o  The program will only read values from JOBS and SALARY_
       HISTORY, so there is no need for PROTECTED or WRITE access.
       However, you do intend to update records in the transaction,
       so the read-only transaction mode is not appropriate.

    Example 4

    In the following example, the user [SQL,HALSTON] receives the
    READ, WRITE, MODIFY, and ERASE rights. HALSTON also gets the
    DISTRIBTRAN right, which allows HALSTON to run the two-phase
    commit protocol on the current database.

    RDO> DEFINE PROTECTION FOR DATABASE
    cont> POSITION 2
    cont> IDENTIFIER [SQL,HALSTON]
    cont> ACCESS "READ+WRITE+MODIFY+ERASE+DISTRIBTRAN".
    RDO>
    RDO> SHOW PROTECTION FOR DATABASE
        (IDENTIFIER=[SQL,RICK],ACCESS=READ+WRITE+MODIFY+ERASE+SHOW+DEFINE+
          CHANGE+DELETE+CONTROL+OPERATOR+ADMINISTRATOR+REFERENCES+SECURITY+
          DISTRIBTRAN)
        (IDENTIFIER=[SQL,HALSTON],ACCESS=READ+WRITE+MODIFY+ERASE+DISTRIBTRAN)
        (IDENTIFIER=[*,*],ACCESS=NONE)

    Example 5

    The following START_TRANSACTION statement starts a read/write
    transaction reserving the EMPLOYEES table for shared read. Note
    that the SHOW TRANSACTION statement shows that fast commit is
    enabled for the database.

    RDO> START_TRANSACTION READ_WRITE RESERVING
    cont> EMPLOYEES FOR SHARED READ
    RDO> SHOW TRANSACTION
    All Transactions in Database with filename MF_PERSONNEL
    a read-write transaction is in progress
      - updates have not been performed
      - fast commit is enabled
      - transaction sequence number (TSN) is 121
      - snapshot space for TSNs less than 121 can be reclaimed
      - session ID number is 42