Sybase 12.4.2 사용자 설명서

Overview of transactions and versioning

 

Transactions are atomic. In other words, Adaptive Server IQ executes all the 
statements within a transaction as a unit. At the end of each transaction, 
changes can be committed to make them permanent. If for any reason all the 
commands in the transaction do not process properly, then some or all of the 
intermediate changes can be undone, or rolled back. The user application 
controls the conditions under which changes are committed or rolled back. In 
DBISQL the 

AUTO_COMMIT

 option can be used to control commits and 

rollbacks automatically.

Transactions break the work of each user into small blocks. The completion of 
each block marks a point at which the information is self-consistent. 
Transaction processing is fundamental to ensuring that a database contains 
correct information.

Adaptive Server IQ processes transactions quite differently from the way 

Adaptive Server Anywhere does when it operates without IQ. This chapter 
describes how Adaptive Server IQ handles transactions. If you are working in 
an Anywhere-only database, see the Adaptive Server Anywhere User’s Guide 
for information on transactions and locking.

Adaptive Server IQ allows commands to be grouped into transactions. In most 
cases, IQ transactions begin and end automatically, based on the commands 
being issued, and the options set. You can also issue explicit commands to 
begin or end a transaction.

Transactions start automatically with one of the following events:

•

The first statement following a connection to a database.

•

The first statement following the end of a previous transaction.

Transactions complete with one of the following events:

•

A 

COMMIT 

statement makes the changes to the database permanent.