ObjectDB ObjectDB

Internal Website Search

171-180 of 200 resultsRefresh

Shared (L2) Entity Cache

- every entity class which is not marked with @Cacheable inherits cacheability setting from its super ... automatically: On retrieval - shared cache is used for entity objects that are not in the persistence context. If an entity object is not available also in the shared cache - it is retrieved from

Literals in JPQL and Criteria Queries

), a feature that is not currently supported by all JPA implementations. String Literals JPQL follows ... ", "abcd\n1234") but this is not supported by all the JPA implementations. Unlike most other JPQL components, String literals (which represent data) are case sensitive, so 'abc' and 'ABC' are not


entities to become detached. Changes made to entities that have not been flushed to the database will not ... - if not an entity Since: JPA 1.0 Query createNamedQuery(String name) Create an instance of Query ... : IllegalArgumentException - if a query has not been defined with the given name or if the query

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

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

Strings in JPQL and Criteria Queries

Pattern Matching with Wildcards The [NOT] LIKE operator checks if a specified string matches ... '%' is always TRUE (for any c.name value). c.name NOT LIKE '%' is always FALSE (for any c.name value ... character is 1. Zero (0) is returned if the substring is not found. The third argument


. 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

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

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

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

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.

Need Help?

  1. Search ObjectDB website
  2. Read the FAQ
  3. Follow the Tutorials
  4. View or post in the forum
  5. Search or file an issue
  6. Contact support