Transaction processing and concurrent control in the ORMLITE JDBC framework

Affairs processing and concurrent control in the ORMLITE JDBC framework introduction: Affairs processing and concurrent control are two key concepts in the modern database system.Essence processing ensures that a set of database operations are all successful or all fails; concurrent controls are managed by multiple transactions to ensure the consistency of the database.This article will focus on how to handle transactions and control in the ORMLITE JDBC framework. Transaction processing: Affairs is a set of logic units for database operations. It is either completely successful or completely failed.In Oremlite, we can use the `TransactionManager.Callintransaction () method to define and execute a transaction.The following is a simple example: TransactionManager.callInTransaction(connectionSource, new Callable<Void>() { @Override public Void call() throws Exception { // Perform database operations in transactions // ... return null; } }); In the above example, we used anonymous internal classes to implement the `Callable` interface, and rewrite the` Call () "method. In this method, the database operation that needs to be performed in the transaction is defined. Concurrent control: ORMLITE provides several ways to deal with concurrent control to prevent conflicts between database operations.Here are some common concurrent control mechanisms: 1. Optimistic lock: Optimistic lock is a way to manage concurrency through version control.The physical classes in Oremlite can use the `@version` annotation to define a version field, which is used for concurrent control.When the two transactions are updated at the same time, the ORMLITE will automatically detect the version conflict and throw out the abnormality of the `OptimisticLockexception`, you can choose to retrieve or roll back the transaction during abnormal processing. @DatabaseTable(tableName = "my_entity") public class MyEntity { // ... @Version private int version; } 2. Pessy lock: The pessimistic lock is managed and parallel by monopolizing locks.The `dao` object in Oremlite provides a method of` lockObjects () `to achieve pessimistic locks.The following is an example: Dao<MyEntity, Integer> dao = DaoManager.createDao(connectionSource, MyEntity.class); MyEntity entity = dao.queryForId(1); dao.lockObjects(Collections.singleton(entity)); // Execute operations // ... dao.unlockObjects(Collections.singleton(entity)); In the above examples, we first obtained a physical object through the `QueryForid ()" method, and then lock the object with the method of `lockObjects ()`.After the operation is completed, we use the method of `unlockObjects () to unlock. 3. Compassion locking with transactions: Pessy locks can also be used with transactions to achieve more complicated concurrency control.For example, we can lock multiple objects in one transaction and then perform related database operations.The following is an example: Dao<MyEntity, Integer> dao = DaoManager.createDao(connectionSource, MyEntity.class); MyEntity entity1 = dao.queryForId(1); MyEntity entity2 = dao.queryForId(2); TransactionManager.callInTransaction(connectionSource, new Callable<Void>() { @Override public Void call() throws Exception { dao.lockObjects(Arrays.asList(entity1, entity2)); // Execute operations // ... return null; } }); In the above examples, we lock two physical objects in one transaction and perform related database operations in transactions. in conclusion: In the ORMLITE JDBC framework, transaction processing and concurrent control are the key mechanisms to ensure the correctness and consistency of the database operation.By using the method of using the `TransactionManager.Callintransaction () method, we can define and execute transactions.With optimistic locking and pessimistic ways, we can effectively control the concurrent operation to ensure the integrity of the data. I hope this article will help you understand the transaction processing and concurrency control in Oremlite.For more detailed information, please refer to the ORMLITE official documentation. (This article only provides basic concepts and examples, and does not cover all details. The specific implementation needs to be carried out according to actual needs) Appendix: ORMLITE official document link: http://ormlite.com/docs/