ObjectDB Database Search

and for representing query results as tuples. SELECT Clause Elements The content of the SELECT ... ;for more details and examples. Query Results as Tuples JPA 2 introduces a new way to represent multi selection results (i.e. results of a query with multiple expressions in the SELECT clause) using

= em. createQuery ("SELECT c FROM Country c", Country.class); List results = query. getResultList (); Because the results are managed entity objects they have all the support that JPA provides ... detection , support for delete , etc. Query results are not limited to entity objects. JPA 2 adds

. Result Range (setFirstResult, setMaxResults) The setFirstResult and  setMaxResults methods enable defining a result window that exposes a portion of a large query result list (hiding anything outside that window). The setFirstResult method is used to specify where the result window begins, i.e

- for use when exactly one  result object is expected. Query.getResultList - for general use in any ... .getSingleResult - for use when exactly one  result object is expected. TypedQuery.getResultList ... results = query. getResultList (); Both Query and TypedQuery define a getResultList method

JPA Method in javax.persistence.criteria.CriteriaBuilder$SimpleCase Expression otherwise (   R  result ) Add an "else" clause to the case expression. Parameters: result - "else" result Return: expression Since: JPA 2.0

JPA Method in javax.persistence.criteria.CriteriaBuilder$SimpleCase Expression otherwise (   Expression   result ) Add an "else" clause to the case expression. Parameters: result - "else" result expression Return: expression Since: JPA 2.0

JPA Method in javax.persistence.criteria.CriteriaBuilder$SimpleCase CriteriaBuilder.SimpleCase when (   C condition,    Expression   result ) Add a when/then clause to the case expression. Parameters: condition - "when" condition result - "then" result expression Return: simple case expression Since: JPA 2.0

JPA Method in javax.persistence.criteria.CriteriaBuilder$SimpleCase CriteriaBuilder.SimpleCase when (   C condition,    R  result ) Add a when/then clause to the case expression. Parameters: condition - "when" condition result - "then" result value Return: simple case expression Since: JPA 2.0

JPA Method in javax.persistence.criteria.CriteriaBuilder$Case CriteriaBuilder.Case when (   Expression  condition,    R  result ) Add a when/then clause to the case expression. Parameters: condition - "when" condition result - "then" result value Return: general case expression Since: JPA 2.0

JPA Method in javax.persistence.criteria.CriteriaBuilder$Case Expression otherwise (   Expression   result ) Add an "else" clause to the case expression. Parameters: result - "else" result expression Return: expression Since: JPA 2.0

JPA Method in javax.persistence.criteria.CriteriaBuilder$Case Expression otherwise (   R  result ) Add an "else" clause to the case expression. Parameters: result - "else" result Return: expression Since: JPA 2.0

JPA Method in javax.persistence.criteria.CriteriaBuilder$Case CriteriaBuilder.Case when (   Expression  condition,    Expression   result ) Add a when/then clause to the case expression. Parameters: condition - "when" condition result - "then" result expression Return: general case expression Since: JPA 2.0

The ORDER BY clause specifies a required order for the query results . Any JPQL query that does not include an ORDER BY clause produces results in an undefined and non-deterministic order. ORDER BY ... produces objects for examination and the WHERE clause selects which objects to collect as results

of countries that do not share a border, returning as results only neighboring countries. Caution ... part of any iterated pair and is therefore excluded from the query results . INNER JOIN simply skips any ... could also cause performance problems. For example, let's look at the following query execution and result

the result is FALSE , because one FALSE operand is sufficient for a FALSE result . If one operand is NULL and the other operand is either TRUE or NULL , the result is NULL (unknown). ObjectDB supports ... the result is TRUE , because one TRUE operand is sufficient for a TRUE result . If one operand is NULL

should be used mainly when the query result type is unknown or when a query returns polymorphic results and the lowest known common denominator of all the result objects is Object . When a more specific result type is expected queries should usually use the TypedQuery interface. It is easier to run

of the two cache mechanisms that ObjectDB manages for queries: The results attribute specifies the size of the query result cache. Caching results is very useful for recurring queries with identical arguments. As long as the relevant data in the database is unchanged cached results can be returned instead

the result range. Check [Disable Cache] to bypass query program and result caches. Click the Execute ... with the query results , and the size of the result collection and the query execution time ... for the results . On the bottom of the query window there is a log panel that displays the selected

rather than embedding literals dynamically into the query string and results in more efficient queries. @NamedQuery ... receives a query name and a result type and returns a TypedQuery instance: TypedQuery query = em. createNamedQuery ("Country.findAll", Country.class); List results = query. getResultList

fast - much faster than any other JPA solution. General Highly optimized code (as a result of many profiling sessions). Unique data structures and algorithms (as a result of years of R&D). Outperforms ... . Query program cache (for repeating queries with different arguments). Query result cache (for repeating

clause. Finally, the range variable, c , is also used in the SELECT clause as the query result expression. CriteriaQuery TypedQuery TypedQuery TypedQuery query = em. createQuery (q); List results ... =      em. createQuery ("SELECT c FROM Country c", Country.class); List results

resulting from mechanical transformation or translation of a Source form, including but not limited ... , incidental, or consequential damages of any character arising as a result of this License or

") List employees; } In that case the employees  field is filled with the results ... from the inverse query results by specifying a selected key field using the MapKey annotation

all the recorded operations. The resulting database file is also generated in the recording directory as .odb ... 1000 are applied, the generated result file is expected to be 1000.odb .

and JDO. JPA follows Java numeric promotion principles. For example, the resulting type ... the same type the result type is the same. If the two operands have different types, numeric promotion

objects to the SELECT clause for collecting as query results , the WHERE clause gets an opportunity ... evaluates to TRUE are passed to the SELECT clause and then collected as query results . WHERE Predicate

and eliminates the ORM layer. The result is better performance and faster applications, especially when the object data model is complex. See JPA benchmark results ...   Reduce development time. Improve

Query parameters enable the definition of reusable queries. Such queries can be executed with different parameter values to retrieve different results . Running the same query multiple times ... ). getSingleResult (); } The WHERE clause reduces the query results to Country objects whose name field value

, and if a court requires any other Contributor to pay any damages as a result , the Commercial ... arose. Each party waives its rights to a jury trial in any resulting litigation.

Existing entity objects can be deleted from the database either explicitly by invoking the remove method or implicitly as a result of a cascade operation. Explicit Remove In order to delete ... a remove operation. To avoid dangling references as a result of orphan removal this feature

. The on-persist attribute specifies whether cascading (as a result of either global or local setting) should be applied during persist. The on-commit attribute specifies whether cascading (as a result

The GROUP BY clause enables grouping of query results . A JPQL query with a GROUP BY clause returns properties of generated groups instead of individual objects and fields. The position of a GROUP BY ... which returns the first letters as result . ObjectDB is very flexible in allowing JPQL expressions anywhere in

, such as query results that contain millions of objects. The element specifies temporary file settings ... , which specifies when network sockets become obsolete as a result of inactivity. The value is the timeout

JPA 2 supports both optimistic locking and pessimistic locking . Locking is essential to avoid update collisions resulting from simultaneous updates to the same data by two concurrent users. Locking ... can also be set for a query in order to lock all the query result objects. When a retrieval operation includes

New entity objects can be stored in the database either explicitly by invoking the persist method or implicitly as a result of a cascade operation. Explicit Persist The following code stores an instance of the Employee entity class in the database: Employee employee = new Employee("Samuel

out of, or related to, use of the Software. 6. The Customer may not disclose the  results of any

String values may appear in JPQL queries in various forms: as  string literals - e.g. 'abc' , ''. as parameters - when string values are assigned as arguments. as  path expressions - in navigation to persistent string fields. as results of predefined JPQL string manipulation functions

Date and time expressions may appear in JPQL queries: as date and time literals - e.g. {d '2011-12-31'} , {t '23:59:59'} . as parameters - when date and time values are assigned as arguments. as  path expressions - in navigation to persistent date and time fields. as results of predefined

for sorting results and for projection: SELECT MIN(p.x) FROM Point p WHERE p.x

defines the query results . The query above simply returns all the Country objects from the iteration

to prevent extraction by the shell. The result output message lists the classes

to boost recycling rates in Manchester approved n criteria, and iteration over the results in ... result is a subset of objects from the candidate collection that contains only the instances ... result = (Collection)query.execute(); Queries are represented by the javax.jdo.Query interface. A Query

) and high ( 20 ): You may click Preview Results  to see the query results : Close the dialog box by

, you may download and run the result application as a Maven project: JPA Web App - Maven Project (6KB

)); // Prepare the result view (guest.jsp): return new ModelAndView("guest.jsp", "guestDao", guestDao

;if you prefer, you may download and run the result application as a Maven project: Java EE JPA Web

"); if (name != null) guestDao.persist(new Guest(name)); // Prepare the result view (guest.jsp): return

) is opened with the query results and the size of the result collection and the query execution time ... ). This opens the specified viewer window type and displays the results . On the bottom of the query

. Objects stored as a result of persistence by reachability can be embedded. By default, system types ... , sophisticated queries. The results can also be sorted by specified order expressions. Chapter 7 is devoted

; An attempt to run the program now results in the following error: Error: Class 'Person' is not