Transaction management in Java EE--Transaction overview (1)

Today is going to talk about business management, the reader may or may not understand, in fact, it is very simple (Daniel please bypass). Originally wanted to quote an idiom of what to describe the characteristics of the transaction, but racking also did not find the appropriate, so found the following sets of idioms to describe the transactional. In fact, the description of the transaction in the official document is divided into four aspects. This is explained by your own understanding.

The first pair of words is: "open bow No Back arrow" and "Naught" (fall short? Choke ）

This pair of words together to see is the atomic nature of the transaction, is what we usually say to do to finish, or do not do a bit. One of the previous finishes is to show that the transaction has been successful, and what is said later is that the transaction needs to be rolled back when execution fails, that is, it remains the same (refer to the next feature-consistency).

The second pair of words is: "tight-lipped" and "Say What"

This combination of words is a matter of consistency, meaning that after the end of a transaction then the data will be valid, not incomprehensible. In other words, this feature is a supplement to the previous feature, do half do not want to do, that I am sorry you have to restore my original, not a part of the data changes, the other part has not changed.

The third pair of words is: "Do not have the An armchair" and "each sweep their own front of the snow, Mo Guan Others wa Frost"

The translation of the words into vernacular is "a matter of my own business", which describes another feature of the transaction--isolation. That is, there is no relationship between the different transactions, and when the transaction commits other transactions to see the change, otherwise it is like a black box for the external transaction and does not know what is inside.

The four words are: "Dust settles" and "Mehujael"

The meaning of the words is that everything has been done, and don't want to regret it. The attribute that maps to a transaction is persistence. Once the transaction is complete, it means that the changes made in the transaction will continue, and of course, the other transaction is changed after another matter.

The official document says that meeting the four characteristics of the above-mentioned business is calledACIDtransactions, wherea:atomicity,C:Consistency,I:Isolation,D:Durability). But in satisfyingACIDattributes, people take into account that performance issues are a flexible strategy. such as the isolation level of data, people can prescribe more lenient or stricter rules than before. (Refer to Wikipedia's "transaction isolation" entry for details.) People are prescribed to improve performance, or to get more consistent data.

Transaction management in Java EE--Transaction overview (1)