Spring Transaction（1）
阿新 • • 發佈：2019-02-16
1. What is transaction?
This is the definition from wiki :
A transaction symbolizes a unit of work performed within a database management system (or similar system) against a database, and treated in a coherent and reliable way independent of other transactions. A transaction generally represents any change in a database. Transactions in a database environment have two main purposes:
- To provide reliable units of work that allow correct recovery from failures and keep a database consistent even in cases of system failure, when execution stops (completely or partially) and many operations upon a database remain uncompleted, with unclear status.
- To provide isolation between programs accessing a database concurrently. If this isolation is not provided, the programs' outcomes are possibly erroneous.
A database transaction, by definition, must be atomic, consistent, isolated and durable.[1] Database practitioners often refer to these properties of database transactions using the acronym ACID.
Transactions provide an "all-or-nothing" proposition, stating that each work-unit performed in a database
From my perspective, it is an all-or-nothing and isolated unit of work performed within a database management system against a database.
2. Three important interfaces in transaction
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PlatformTransactionManager
Method Summary
| Modifier and Type | Method and Description |
|---|---|
void |
Commit the given transaction, with regard to its status. |
| Return a currently active transaction or create a new one, according to the specified propagation behavior. | |
void |
Perform a rollback of the given transaction. |
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TransactionDefinition
-
Field Summary
Modifier and Type Field and Description static intUse the default isolation level of the underlying datastore. static intIndicates that dirty reads are prevented; non-repeatable reads and phantom reads can occur. static intIndicates that dirty reads, non-repeatable reads and phantom reads can occur. static intIndicates that dirty reads and non-repeatable reads are prevented; phantom reads can occur. static intIndicates that dirty reads, non-repeatable reads and phantom reads are prevented. static intSupport a current transaction; throw an exception if no current transaction exists. static intExecute within a nested transaction if a current transaction exists, behave like PROPAGATION_REQUIREDelse.static intDo not support a current transaction; throw an exception if a current transaction exists. static intDo not support a current transaction; rather always execute non-transactionally. static intSupport a current transaction; create a new one if none exists. static intCreate a new transaction, suspending the current transaction if one exists. static intSupport a current transaction; execute non-transactionally if none exists. static intUse the default timeout of the underlying transaction system, or none if timeouts are not supported.
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Method Summary
Modifier and Type Method and Description intReturn the isolation level. java.lang.StringReturn the name of this transaction. intintReturn the transaction timeout. booleanReturn whether to optimize as a read-only transaction.
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TransactionStatus
Method Summary
| Modifier and Type | Method and Description |
|---|---|
void |
flush()
Flush the underlying session to the datastore, if applicable: for example, all affected Hibernate/JPA sessions.
|
boolean |
Return whether this transaction internally carries a savepoint, that is, has been created as nested transaction based on a savepoint. |
boolean |
Return whether this transaction is completed, that is, whether it has already been committed or rolled back. |
boolean |
Return whether the present transaction is new (else participating in an existing transaction, or potentially not running in an actual transaction in the first place). |
boolean |
Return whether the transaction has been marked as rollback-only (either by the application or by the transaction infrastructure). |
void |
Set the transaction rollback-only. |