Oracle cursor for updating in oracle

25-Oct-2019 18:29

Serializable does not mean that all transactions executed by the users are the same as if they were executed one right after another in a serial fashion.

It does not imply that there is some serial ordering of the transactions that would result in the same outcome.

The following table represents two sessions performing work over time. No matter how many times Session 1 queried table B - the count would be the count that was committed in the database at time .SQL92 takes these three phenomena and creates four isolation levels based on the existence, or lack thereof, of the above phenomena. The SQL92 standard was attempting to set up isolation levels that would permit various degrees of consistency for queries performed in each level.They are: Isolation Level Dirty Read Non-Repeatable Read Phantom Read Read Uncommitted Permitted Permitted Permitted Read Committed Permitted Permitted Repeatable Read Permitted Serializable Oracle supports explicitly two of the above isolation levels as they are defined ? Repeatable read is the isolation level they claim you must be at to get a read consistent result from a query.March 31, 2002 - pm UTC (for the whole story, you can read the chapter in my book that contains pages 130-131 -- I go into this in detail as it is a very important topic to understand).It all stems from the isolation levels defined and how they are defined. These phenomena are (excerpted from my book) The ANSI/ISO SQL92 standard adds to the concurrency control mix as well.

The following table represents two sessions performing work over time. No matter how many times Session 1 queried table B - the count would be the count that was committed in the database at time .SQL92 takes these three phenomena and creates four isolation levels based on the existence, or lack thereof, of the above phenomena. The SQL92 standard was attempting to set up isolation levels that would permit various degrees of consistency for queries performed in each level.They are: Isolation Level Dirty Read Non-Repeatable Read Phantom Read Read Uncommitted Permitted Permitted Permitted Read Committed Permitted Permitted Repeatable Read Permitted Serializable Oracle supports explicitly two of the above isolation levels as they are defined ? Repeatable read is the isolation level they claim you must be at to get a read consistent result from a query.March 31, 2002 - pm UTC (for the whole story, you can read the chapter in my book that contains pages 130-131 -- I go into this in detail as it is a very important topic to understand).It all stems from the isolation levels defined and how they are defined. These phenomena are (excerpted from my book) The ANSI/ISO SQL92 standard adds to the concurrency control mix as well.Read committed does not give you consistent results.