Prior knowledge or experience in database programming (SQL, JDBC, ORM, JPA, etc.) is not required, but some background in using the Java language is essential.
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New entity objects can be stored in the database either explicitly by invoking the persist method ... and changes its state to Managed. The new entity object is stored in the database when the transaction ... of an entity class. Only instances of entity classes can be stored in the database independently. Objects
Given an EntityManager, em, that represents a JPA connection to the object database, we can use it to store, retrieve, update and delete database objects. Storing New Entity Objects The following code fragment stores 1,000 Point objects in the database: em.getTransaction().begin(); for (int
As noted above, using ObjectDB instead of a relational database and ORM combination is easier ... database is mandatory (e.g. as a result of a customer request or when a new application is developed for an existing old relational database). By using the Java Persistence API (JPA), you can develop
Detached entity objects are objects in a special state in which they are not managed by any EntityManager but still represent objects in the database. Compared to managed entity objects, detached ... the database unless modified detached objects are merged back into an EntityManager to become managed
Existing entity objects can be deleted from the database either explicitly by invoking the remove ... (); The entity object is physically deleted from the database when the transaction is committed. Embedded ... of that object from the database. DELETE Queries DELETE queries provide an alternative way for removing
Modifying existing entity objects that are stored in the database is based on transparent ... Once an entity object is retrieved from the database (no matter which way) it can simply be modified in memory ... (); The entity object is physically updated in the database when the transaction is committed
In JPA a database connection is represented by the EntityManager interface. Therefore, in order to manipulate an ObjectDB database we need an EntityManager instance. Operations that modify database ... of EntityManagerFactory that represents the relevant database and then we can use that factory instance
entity class. This is done automatically in memory each time the entity object is loaded. The database object is only updated to the new schema when that entity object is stored to the database ... of an entity class are detected by ObjectDB. New entity objects have to be stored in the new class
, but they are easier to use in object oriented languages such as Java. In addition, unlike most other NoSQL databases ... ObjectDB is a unique NoSQL database. It doesn't have the known disadvantages and limitations ... can be used in applications that cannot use conventional non ACID NoSQL databases because of a requirement for a very high level of consistency.
database file Checks a given ObjectDB database file, verifies that it is healthy and valid ... of a corrupted ObjectDB database file Repairs a corrupted ObjectDB database file by creating a new fresh database file and then copying all the recoverable data in the corrupted database file