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Locking in JPA

that has to be updated or deleted is checked. An exception is thrown if it is found out that an update ... field. During commit (and flush), ObjectDB checks every database object that has to be updated or ... some ORM JPA providers) is defined in the entity class or not. Pessimistic Locking The main

Storing JPA Entity Objects

or implicitly as a result of a cascade operation. Explicit Persist The following code stores ... managed by the EntityManager) or by commit. Referenced Embedded Objects The following code stores ... of every reachable object or alternatively by setting automatic cascading persist. Cascading Persist Marking

Retrieving JPA Entity Objects

with data that is retrieved from the database (or from the L2 cache - if enabled). The new entity object ... specifying FetchType.LAZY in either @OneToOne or @ManyToOne annotations (currently ObjectDB does not ... in @OneToMany or @ManyToMany annotations (currently ObjectDB does not distinguish between

JPA / JDO Class Enhancer

of a class (without .class suffix) in the CLASSPATH <filename> - path to class or jar file(s ... for enhanced classes You can specify class files and jar files for enhancement explicitly or by using ... can also be passed to the enhance method as a single string delimited by commas or spaces. In

Paths and Types in JPQL and Criteria API

with an instance of a user defined class (represented by a variable, parameter or prefix path expression ... must contain a persistent field (or property) with a matching name. The path expression ... , a NullPointerException is thrown on any attempt to access a field or a method via a null reference. In JPQL

GROUP BY and HAVING clauses

clause. When a GROUP BY clause exists in a JPQL query, database objects (or tuples of database objects ... calculations (count, sum, avg, max, min) that are carried out on all the objects (or the object tuples) in ... clause in which all the FROM/WHERE objects (or object tuples) are considered as one group. For example

Setting and Tuning of JPA Queries

execution if invoked before a query is run using getResultList or getSingleResult. Result Range ... or at the level of a specific query, by overriding the default EntityManager setting: // Enable ... " (JDO query language) or "ODBQL" (ObjectDB query language). The default is ODBQL, which is a union

Strings in JPQL and Criteria Queries

characters: The percent character (%) - which matches zero or more of any character. The underscore character ... for a match (usually a path expression) and the right operand is always the pattern (usually a parameter or ... ). To match an actual underscore or percent character it has to be preceded by an escape character

ObjectDB License

covers installation of ObjectDB on all computers of one company or organization in one building, and in ... that workplace. Servers that are leased or rented from third party web hosting and/or cloud hosting ... , for using ObjectDB in academic courses or in research projects. You may apply using a support

Obtaining a JPA Database Connection

persistence unit in an XML file or you can simply provide the file path of the ObjectDB database ... unit name as an argument, but when using ObjectDB, any valid database file path (absolute or relative) is also accepted. Any string that starts with the prefix objectdb: or ends with .odb or .objectdb

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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