Supported Transaction Isolation Levels in Oracle

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What Are Transaction Isolation Levels Supported by Oracle in Oracle?

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A

Oracle supports two transaction isolation levels:

READ COMMITTED (the default option). If the transaction contains DML that requires row locks held by another transaction, then the DML statement waits until the row locks are released.
SERIALIZABLE. If a serializable transaction contains data manipulation language (DML) that attempts to update any resource that may have been updated in a transaction uncommitted at the start of the serializable transaction, then the DML statement fails.

⇒Understanding SQL Transaction Management in Oracle

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