1. Atomicity:
A thing is an indivisible unit
2. Consistency;
Thing is to make a database from one consistent state to another consistent state
3. Isolation;
The implementation of a thing can not be anything else interference
4. endurance:
Once you have submitted a thing, he changed data in the database should be permanent.
mysql transaction processing:
Only thing innodb database engine supports default innodb database engine, and mysql default execution things, that each have as a SQL transaction processing,
How to manually perform things begin using the keyword display on a thing, use commit or rollback transaction ends.
Second, the problem of concurrent transactions
1, dirty reads: A transaction B reads the data transaction to update and rollback B, then A read data is dirty data
2, non-repeatable read: A transaction reads the same data multiple times, transaction transaction A times B in the course of the read, the data were updated and submitted, the transaction A reads the same data multiple times lead, inconsistent results.
3, Magic Reading: A system administrator will result in the database specific scores for all students from grade ABCDE changed, but the system administrator B would insert a specific record score at this time, when the end of the system administrator A change found there is a record not change overnight, just like happened as hallucinations, this is called phantom reads.
Three, MySQL transaction isolation level
| Transaction isolation level | Dirty read | Non-repeatable read | Magic Reading |
| Uncommitted Read (read-uncommitted) | Yes | Yes | Yes |
| Non-repeatable read (read-committed) | no | Yes | Yes |
| Repeatable Read (repeatable-read) | no | no | Yes |
| Serialization (Serializable) | no | no | no |
Setting things isolation level;
set session transation isolation levle xxxx;