ucsd payroll

not correct, is 2000 yuan, and then quickly rolled back the transaction, modified the amount, the transaction submitted, finally singo the actual wages only 2000 yuan, Singo empty joy a game. The above situation, that is what we call dirty Read, two concurrent transactions, "transaction A: lead to Singo payroll", "Transaction B:singo query Payroll account", transaction B read the transaction A has not yet

omitted.ExampleThe following payroll package already contains the Employee class, and then adds a Boss class to the payroll package. The Boss class can refer to the Employee class without using the payroll prefix, as in the case of the boss class.Boss.java File Code:Package public class boss{ public void Payemployee (Employee e) { e.mailcheck (); }}

For these issues, there is a different level of transaction isolation, which is described in a table below Note: This is the transaction isolation level for MySQL, and Oracle has only read commited and serializable two types. The default isolation level for MySQL is repeatable read,oracle, which is read comiitted. Here are some examples of living things to explain the isolation level of a transaction: READ UNCOMMITTED not submittedThe company paid, the leader of the 5000 yuan to the Singo ac

correct, is 2000 yuan, and then quickly rolled back to business, modify the amount, the transaction will be submitted, and finally singo the actual salary of only 2000 yuan, Singo empty joy a game.The above situation, that is what we call dirty Read, two concurrent transactions, "transaction A: lead to Singo payroll", "Transaction B:singo query Payroll account", transaction B read the transaction A has not

database transactions?There are 4 isolation levels for database transactions, from low to high, READ UNCOMMITTED,Read Committed,Repeatable read, andSerializable, which can be resolved individually by each of the four levels Some problems such as dirty reading, non-repetition reading and phantom reading read UNCOMMITTED READ UNCOMMITTED The company paid, the leader of the 5000 yuan to the Singo account, but the transaction did not submit, and Singo just to check the account, found that t

correct, is 2000 yuan, and then quickly rolled back to business, modify the amount, the transaction will be submitted, and finally singo the actual salary of only 2000 yuan, Singo empty joy a game.The above situation, that is what we call dirty Read, two concurrent transactions, "transaction A: lead to Singo payroll", "Transaction B:singo query Payroll account", transaction B read the transaction A has not

yuan, and then quickly rolled back to business, modify the amount, the transaction will be submitted, and finally singo the actual salary of only 2000 yuan, Singo empty joy a game. The above-mentioned situation is what we call dirty reading, that is, for two concurrent transactions (transaction A: lead to Singo payroll, Transaction B:singo Query Payroll account), transaction B reads the data that transacti

leadership found that the amount of wages issued to Singo is not correct, is 2000 yuan, and then quickly rolled back to business, modify the amount, the transaction will be submitted, and finally singo the actual salary of only 2000 yuan, Singo empty joy a game. The above situation, that is what we call dirty Read, two concurrent transactions, "transaction A: lead to Singo payroll", "Transaction B:singo query Pay