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The DBEnvironment determines both what data can be accessed
in a transaction and what data can be recovered.
Following a failure, a transaction can be recovered, or all data can
be recovered, as follows:
A transaction is one or more SQL statements that together perform
a unit of work on one or more databases in a DBEnvironment. Work done
within a transaction can be made permanent (committed) or undone
(rolled back).
After a system or hardware failure, all data
within a DBEnvironment is recovered to a consistent state. Changes
performed by any transactions incomplete at failure time are rolled
back. Changes performed by transactions completed before failure time
are made permanent.
You can have more than one DBEnvironment on your system. When
you connect to a DBEnvironment, ALLBASE/SQL establishes a DBE
session for you. The query processor can process statements
only when you are in a DBE session. You can access any DBEnvironment
in either of the two following modes:
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