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Please explain. Use the below transaction.

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unrepeatable read happens when a transaction read the value of variable twice or more times and in between these reads other transaction change the value of variable causing different read values for first transaction.

so this whole case cant happen in 2PL because no transaction can come in between reads and take exclusive lock for write the value while there is share lock on variable

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Any 2 PL if does not cause deadlock will ensure conflict serializability.

Now every conflict serializable schedule is free from unrepeatable read problem.

So every strict schedule is free from unrepeatable read problem.

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