| 1 |
When an update (written) occurs, the original data values changed by the update remains part of an uncommitted transaction, any user that later queries the modified data views the original data values
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| 2 |
Only when a transaction is committed are the changes of the transaction made permanent
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| 3 |
Only statements that start after another user's transaction is committed see the changes made by the committed transaction
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| 4 |
A transaction is key to Oracle's RDBMS for providing read-consistency. This unit of committed (or uncommitted) SQL statements :
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dictates the start point for read-consistent views generated on behalf of readers
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controls when modified data can be seen by other transactions of the database for reading or updating
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