1, the concept of transaction
- Is a logical unit to perform the procedure database management system by a finite sequence database consisting of operation;
- All operations performed by the transaction between the start (begin transaction) and the end of the transaction (end transaction) composition;
2, the characteristics of the transaction (ACID)
- Atomicity (Atomicity): A transaction is an indivisible unit of work, operations in the transaction either do or do not do;
- Consistency (Consistency): database transaction must be changed from one consistent state to another consistent state;
- Isolation (Isolation): data can not interfere with each other transactions concurrent isolation of the operation and use of an internal transaction, each transaction performed concurrently;
- Persistent (Durability): Once a transaction is committed, it changed data in the database is permanent.