Transaction basics – PB Docs 2018

CONNECT and DISCONNECT

A successful CONNECT starts a transaction, and a
DISCONNECT terminates the transaction. All SQL statements that execute
between the CONNECT and the DISCONNECT occur within the
transaction.

Before you issue a CONNECT statement, the Transaction object must
exist and you must assign values to all Transaction object properties
required to connect to your DBMS.

COMMIT and ROLLBACK

When a COMMIT executes, all changes to the database since the
start of the current transaction (or since the last COMMIT or ROLLBACK)
are made permanent, and a new transaction is started. When a
ROLLBACK executes, all changes since the start of the current
transaction are undone and a new transaction is started.

When a transactional component is deployed to an application
server, you can use the TransactionServer context object to control
transactions. See Transaction server
deployment.

AutoCommit setting

You can issue a COMMIT or ROLLBACK only if the AutoCommit property
of the Transaction object is set to False (the default) and you have not
already started a transaction using embedded SQL.

For more about AutoCommit, see Description of Transaction object
properties.

Transaction pooling

To optimize database processing, you can code your PowerBuilder
application to take advantage of transaction pooling.

For information, see Pooling database
transactions.

Transaction server
deployment

Components that you develop in PowerBuilder can participate in
transactions in application servers. You can mark components to indicate
that they will provide transaction support. When a component provides
transaction support, the transaction server ensures that the component’s
database operations execute as part of a transaction and that the
database changes performed by the participating components are all
committed or rolled back. By defining components to use transactions,
you can ensure that all work performed by components that participate in
a transaction occurs as intended.

PowerBuilder provides a transaction service context object called
TransactionServer that gives you access to the transaction state
primitives that influence whether the transaction server commits or
aborts the current transaction. COM+ clients can also use the
OleTxnObject object to control transactions. If you use the
TransactionServer context object and set the UseContextObject DBParm
parameter to Yes, COMMIT and ROLLBACK statements called in the
Transaction object will result in a database error.

By default, the TransactionServer context object is not used.
Instead you can use COMMIT and ROLLBACK statements to manage
transactions. In this case, COMMIT is interpreted as a
SetComplete function and ROLLBACK is interpreted as a
SetAbort function.