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5

Schema Update

. The default configuration file contains an empty <schema> element. If the <schema> element is not empty ... to the new package name. In addition, whether or not a new-name attribute is specified, a <package> element ... . The com.example.old3 package is not renamed, but rename operations are specified for some of its classes
5

Deleting JPA Entity Objects

back and not committed the object is not deleted. An IllegalArgumentException is thrown by remove if the argument is not an instance of an entity class or if it is a detached entity ... up dependent objects (e.g. Address) that should not exist without a reference from an owner object (e
5

javax.persistence.TypedQuery

. Returns 0 if setFirstResult was not applied to the query object. Returns: position of the first ... . Get the flush mode in effect for the query execution. If a flush mode has not been set for the query ... Throws: IllegalStateException - if the query is found not to be a Java Persistence query language
5

Database Doctor

, and if the file is not valid (it is corrupted), produces a detailed diagnosis report of all the errors. Repair ... engine (not using one server process), thus bypassing ObjectDB internal file lock protection. Modifying the database file externally not through ObjectDB (e.g. by malicious software such as
5

Query Parameters in JPA

(:) followed by a valid JPQL identifier that serves as the parameter name. JPA does not provide an API ... literals rather than parameters in queries. First of all, the query is not reusable. Different ... of which are overridden in TypedQuery. That large number of methods is not typical to JPA
5

Database Schema Evolution

Modifications to entity classes that do not change their persistent field definitions (their schema ... . Fields in the new schema that do not have matching fields in the old schema are initialized with default values (0, false or null). Fields in the old schema that do not have matching fields in the new
5

Database Connection using JPA

not yet exist a new database file is created. When the application is finished using ... ) and listening on the specified port (the default is 6136 when not specified). The path indicates ... of the managed entity is not affected by the rollback and is not returned to its pre-modified state. Ending
5

Updating JPA Entity Objects

. If the transaction is rolled back and not committed the update is discarded. On commit the persist operation ... . If global cascade persist is enabled all the reachable entity objects that are not managed ... ); em.getTransaction().begin(); employee.projects[0] = new Project(); // not detected
5

GROUP BY and HAVING clauses

the query. Note that the query above might not be supported by some JPA implementations ... (which does not use aggregates) is equivalent to the following query: SELECT DISTINCT SUBSTRING(c ... Aggregates (no GROUP BY) JPQL supports a special form of aggregate queries that do not have a GROUP BY
5

javax.persistence.Query

if setFirstResult was not applied to the query object. Returns: position of the first result Since: JPA 2 ... mode in effect for the query execution. If a flush mode has not been set for the query object ... : IllegalStateException - if the query is found not to be a Java Persistence query language SELECT query or

Getting Started

ObjectDB is very easy to use. Follow the Getting Started Tutorial and the Quick Tour manual chapter and in minutes you may be able to write and run first Java programs against ObjectDB.

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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