Things isolation levels and things propagation properties

things Isolation Level The thing isolation level is to resolve dirty reads, Phantom reads, non-repeatable reads Dirty Read: Data that has not been determined to be committed is read by other things Phantom Reading: The data on the select point of Time is different from the actual situation, which will add data non-repeatable read: The same data is read by multiple things at the same time, multiple things can be simultaneously modified the same data, resulting in inconsistent data. Serialization of SERIALIZABLEThe highest level of things isolation levels things are executed in order: resolved Dirty Read, Phantom Read, non-repeatable read REPEATABLE Read repeatable readsThe data will not be modified while the Select is in progress, but the data can be added to solve the Dirty Read, non-repeatable read, there will be Phantom Reading Read commited reading commitThe thing is released immediately after reading the data. Read Lock, causing other things to modify this data. Solve Dirty Read, there will be Phantom Read, non-repeatable read read uncommited not submittedData can be read by other things when not committed Dirty Read, Phantom Read, non-repeatable read Things Propagate Properties REQUIRED

A transaction already exists, the transaction is joined, or a new transaction is created.
Spring default propagation behavior requires_new creates new things, suspends this thing if there is already a thing, SUPPORTS If there exists a thing and then joins it, otherwise runs in the Nothing mode Not_supported runs in a nothing mode, if there is something to suspend the thing MANDATORY force the use of things, there is no thing to throw an exception NESTED The current existence of transactions, The method is run in a nested transaction. A nested transaction can be committed and rolled back separately from the current transaction. If there is no transaction, create a new transaction never run in a nothing environment, or throw an exception if something is present