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Pessimistic lock

WORM (Write once read many) support

Internal ObjectDB error by read the primary key

Failed to read the value of field using reflection (error 363)

Have read read the documentation on optimistic locks, still not sure how to deal ... . But you can disable optimistic locking in the server configuration .   support Support read the documentation ... - since someone can change the object just after the refresh . In that case - use pessimistic locks. support

The best source for learning ObjectDB is the ObjectDB Manual , which contains all the necessary information for using ObjectDB. The only required background is a good understanding of the Java language. Reading the manual and getting started with ObjectDB could be easier for developers with prior

Please read the ObjectDB licence page.

more detail how to use the EntityManager and transactions for create, read , update, and delete (CRUD) database operations.

This chapter explains how to manage ObjectDB databases by using Jakarta Persistence (JPA). The first two pages introduce basic JPA interfaces and concepts: The next section explains how to use JPA for database CRUD (create, read , update, and delete) operations: The final section discusses advanced topics, such as locking and events:

can contain the following permissions: access : Permission to open a database for reading . modify

This chapter demonstrates basic ObjectDB and JPA concepts by introducing a simple example program. After reading this chapter, you will be able to write basic programs that create, open, and close ObjectDB databases and perform basic CRUD (Create, Retrieve, Update, and Delete) operations

create the readings in one call and I try to read them in another call. I checked the database and all the entities are created (document and readings ) but when I try to get the collection of readings null is returned. I have tried to clear the entity manager in the second call to make sure the reading

there. If the entity is found within the persistence context and the lock mode type is pessimistic ... mode type is pessimistic and the entity instance is found but cannot be locked ... - if pessimistic locking fails and the transaction is rolled back. LockTimeoutException - if pessimistic

within the persistence context and the lock mode type is pessimistic and the entity has a version ... is pessimistic and the entity instance is found but cannot be locked: the PessimisticLockException is thrown ... if the entity does not exist. Throws: PessimisticLockException - if pessimistic locking fails

there. If the entity is found within the persistence context and the lock mode type is pessimistic and the entity ... type is pessimistic and the entity instance is found but cannot be locked ... : PessimisticLockException - if pessimistic locking fails and the transaction is rolled back. LockTimeoutException

is pessimistic and the entity has a version attribute, the persistence provider must perform ... , the OptimisticLockException is thrown. If the lock mode type is pessimistic and the entity instance is found ... - if pessimistic locking fails and the transaction is rolled back. LockTimeoutException - if pessimistic

- if pessimistic locking fails and the transaction is rolled back. LockTimeoutException - if pessimistic locking fails and only the statement is rolled back. PersistenceException - if the query execution

.lock.scope property for pessimistic locking. This property may be passed as an argument ... Persistence (JPA) 1.0 NORMAL This value defines the default behavior for pessimistic locking

=REFRESH . If the lock mode type is pessimistic and the entity instance is found but cannot be locked ... : PessimisticLockException - if pessimistic locking fails and the transaction is rolled back. LockTimeoutException - if pessimistic locking fails and only the statement is rolled back. EntityNotFoundException

is pessimistic and the entity instance is found but cannot be locked: the PessimisticLockException ... : PessimisticLockException - if pessimistic locking fails and the transaction is rolled back. LockTimeoutException - if pessimistic locking fails and only the statement is rolled back. EntityNotFoundException

. If the lock mode type is pessimistic and the entity instance is found but cannot be locked ... - if pessimistic locking fails and the transaction is rolled back. LockTimeoutException - if pessimistic locking fails and only the statement is rolled back. EntityNotFoundException - if the entity

when data is read from the database and when data is written to the database. USE indicates ... REFRESH Insert/update entity data held in the cache when read from the database and when written to the database. Force refresh of cache for items read from database. Since: Jakarta Persistence (JPA) 1.0

language UPDATE or DELETE statement. PessimisticLockException - if pessimistic locking fails and the transaction is rolled back. LockTimeoutException - if pessimistic locking fails

. LockTimeoutException - if pessimistic locking fails and only the statement is rolled ... timeout value set and only the statement is rolled back. PessimisticLockException - if pessimistic locking

language UPDATE or DELETE statement. LockTimeoutException - if pessimistic locking fails ... back. PessimisticLockException - if pessimistic locking fails and the transaction is rolled

- if pessimistic locking fails and the transaction is rolled back. LockTimeoutException - if pessimistic locking

DELETE statement. LockTimeoutException - if pessimistic locking fails and only the statement ... back. PessimisticLockException - if pessimistic locking fails and the transaction is rolled back. PersistenceException

query language UPDATE or DELETE statement. PessimisticLockException - if pessimistic locking fails and the transaction is rolled back. LockTimeoutException - if pessimistic locking fails

DELETE statement. PessimisticLockException - if pessimistic locking fails and the transaction is rolled back. LockTimeoutException - if pessimistic locking fails and only the statement is rolled

. LockTimeoutException - if pessimistic locking fails and only the statement is rolled back. NonUniqueResultException ... value set and only the statement is rolled back. PessimisticLockException - if pessimistic locking

Thrown by the persistence provider when a pessimistic locking conflict occurs. This exception

the persistence provider when a pessimistic locking conflict occurs that does not result in

no longer exists in the database. Thrown when EntityManager.lock is used with pessimistic locking is used

Default pessimistic lock timeout hint. Since: Jakarta Persistence (JPA) 1.0 QUERY_TIMEOUT Default

is read from the database via the EntityManager.find methods and execution of queries. USE indicates that data may be read from the second-level cache. BYPASS indicates that data may not be read from ... the database. Since: Jakarta Persistence (JPA) 1.0 USE Read entity data from the cache: this is the default

pessimistic locking only? I've tried various xml configurations, and also various transaction ... , that setting is for optimistic locking. My question was about pessimistic locking (specifically, pessimistic write locking). Your documentation seems unclear about that.   dmoshal David Moshal

Probably a simple answer for someone who's been using ObjectDB for awhile: I'm reading objects ... .getSelectedValue(),       LockModeType. PESSIMISTIC _WRITE); . . } //doEdit ... , LockModeType. PESSIMISTIC _WRITE);         System.out.println

guess I should read doco more. I ran into the same error from a pessimistically locked entity (global ... . Also have the Explorer open Questions: a) what is it about? b) is there a setting for pessimistic mode? In my app ... on pessimistically tracked entity.   Modified conf file, and got the test case working perfectly.  

and roll back. T1 T2 ---------------------------------------------------------- READ (A) version=1 value=0 | READ (B) version=1 value=0 | | READ (A) version=1 value=0 | READ (B) version=1 value=0 | B ... Thread[Thread-2,5,main] READ   A1 version=1 value=0 Thread[Thread-2,5,main] READ   B2 version=1

Jakarta Persistence (JPA) Enum Constant in jakarta.persistence.PessimisticLockScope NORMAL This value defines the default behavior for pessimistic locking. The persistence provider must lock the database row(s) that correspond to the non-collection-valued persistent state of that instance

Jakarta Persistence (JPA) Field in jakarta.persistence.PersistenceConfiguration LOCK_TIMEOUT Default pessimistic lock timeout hint. Since: Jakarta Persistence (JPA) 1.0

; support Support A possible solution (which is currently not implemented) is to use pessimistic locking ... want to use Pessimistic Lock as a way of enforcing a cluster wide singleton of services, a pessimistic ... adds automatic release of pessimistic locks on client-server disconnection. The locks

Jakarta Persistence (JPA) Enum Constant in jakarta.persistence.CacheStoreMode USE Insert entity data into cache when read from database and insert/update entity data when written to the database: this is the default behavior. Does not force refresh of already cached items when reading from database. Since: Jakarta Persistence (JPA) 1.0

Jakarta Persistence (JPA) Enum Constant in jakarta.persistence.CacheStoreMode REFRESH Insert/update entity data held in the cache when read from the database and when written to the database. Force refresh of cache for items read from database. Since: Jakarta Persistence (JPA) 1.0

in the database changes between reading the state of an entity instance and attempting to update or

Jakarta Persistence (JPA) Enum Constant in jakarta.persistence.CacheRetrieveMode USE Read entity data from the cache: this is the default behavior. Since: Jakarta Persistence (JPA) 1.0

server and open the database file in ObjectDB Explorer : This is the end of the tutorial. Learn more about ObjectDB and JPA by reading the Manual .

of the tutorial. Learn more about ObjectDB and JPA by reading the Manual .

enabled without specifying a Java agent. This is the end of the tutorial. Learn more about ObjectDB and JPA by reading the Manual .

. One is to stupidly commit the transaction after a certain number of read accesses (every 10000 read access ... updates to the database or it is read only. If it is a read only operation, do you really need commit ... for posting questionable code snippets. I have repaired it. In this scenario the data is only read