Internal Website Search

declares one or more query variables (also known as identification variables ). Query variables are similar to loop variables in programming languages. Each query variable represents iteration over objects in the database. A query variable that is bound to an entity class is referred to as a range

The FROM clause declares query identification variables that represent iteration over objects in the database. A query identification variable is similar to a variable of a Java enhanced for loop in ... are query identification variables that iterate over all the database objects of a specific entity

for representing the built query . Then a Root  instance is created to define a range variable in the FROM clause. Finally, the range variable , c , is also used in the SELECT clause as the query result ... The JPA Criteria API provides an alternative way for defining JPA queries , which is mainly useful

The interfaces in this group are in use for setting a criteria query FROM clause. Criteria Query Variables The FROM clause  in JPA queries (as in SQL) defines the query variables . Query variables are represented in criteria queries by descendant interfaces of the From interface: Range

of SELECT queries . DELETE queries cannot include multiple variables and JOIN, and cannot include the GROUP ... DELETE queries provide an alternative way for deleting entity objects. Unlike SELECT queries , which are used to retrieve data from the database, DELETE queries do not retrieve data from

;within an active transaction. Applying changes to the database by calling the commit method. JPQL UPDATE queries provide an alternative way of updating entity objects. Unlike SELECT queries , which are used to retrieve data from the database, UPDATE queries do not retrieve data from the database

elements (representing range variables , join and fetch): Other criteria query expressions (for all the query clauses): ... Queries are represented in JPA by the Query and TypedQuery interfaces: The JPA Query API ... these interfaces to build and run JPQL queries . The TypedQuery interface (or alternatively the older Query

of JPQL / Criteria query expressions. Atomic Expressions The atomic query expressions are: JPQL / Criteria Variables JPQL / Criteria Parameters JPQL / Criteria Literals Every query expression consists ... Query expressions are the foundations on which JPQL and criteria queries are built. Every query

Variable Paths: Root country = query . from (Country.class); Join neighborCountry = country. join ... a variable to the FROM clause (representing iteration during query execution). The constructed variable ... classes) are represented in JPQL by the following types of expressions: Variables - FROM

indexes are defined. WHERE Filter in Multi Variable Queries In a multi- variable query the FROM clause ... the WHERE clause are passed through to the SELECT. In multi- variable queries the number of tuples for iteration ... JPQL query that retrieves selective objects from the database. Out of the four optional clauses

The  Query and  TypedQuery interfaces define various setting and tuning methods that may affect query execution if invoked before a query is run using getResultList or getSingleResult ... defining a result window that exposes a portion of a large query result list (hiding

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 with different parameter values (arguments) is more efficient than using a new query string for every query

Hi, I have a case where I have a JPQL query like: "select o from MyEntity o WHERE (enumField IN ... ; query .setParameter("enumFieldList",         Arrays.asList(MyEnumType.VALUE1, MyEnumType.VALUE2)); Then query .getResultSet() *always* returns an empty list

The Query interface defines two methods for running SELECT queries : Query .getSingleResult - for use when exactly one result object is expected. Query .getResultList - for general use in any ... other case. In addition, the Query interface defines a method for running DELETE and UPDATE queries

A named query is a statically defined query with a predefined unchangeable query string. Using named queries instead of dynamic queries may improve code organization by separating the JPQL query strings from the Java code. It also enforces the use of query   parameters

, the following query returns Country objects that become managed by the EntityManager em : TypedQuery query = em. createQuery ("SELECT c FROM Country c", Country.class); List results = query . getResultList ... detection , support for delete , etc. Query results are not limited to entity objects. JPA 2 adds

Queries are represented in JPA 2 by two interfaces - the old Query interface, which was the only interface available for representing queries in JPA 1, and the new TypedQuery interface that was introduced in JPA 2. The TypedQuery interface extends the Query interface. In JPA 2 the Query interface

The ORDER BY clause specifies a required order for the query results. Any JPQL query that does not ... Expressions The following query returns names of countries whose population size ... expressions in the SELECT clause are allowed in the ORDER BY clause. The following query , for example

The GROUP BY clause enables grouping of query results. A JPQL query with a GROUP BY clause returns ... clause in the query execution order is after the FROM and WHERE clauses, but before the SELECT clause. When a GROUP BY clause exists in a JPQL query , database objects (or tuples of database objects

The JPA Query Language (JPQL) can be considered as an object oriented version of SQL. Users ... well as how to use the JPA Criteria API, which provides an alternative way for building queries in JPA ... (named) queries . It explains how to use the relevant interfaces, annotations, enums and methods

and for representing query results as tuples. SELECT Clause Elements The content of the SELECT clause in a criteria query is represented by Selection : Because Selection  is a super interface ... of Selection : See the SELECT in Criteria Queries section for more details and examples. ORDER BY

Date and time expressions may appear in JPQL queries : as date and time literals - e.g. {d '2011-12 ... that are evaluated to the date and time on the database server when the query is executed: CURRENT_DATE ... to 0 . Date and Time in Criteria Queries The CriteriaBuilder interface provides three factory methods

Collections may appear in JPQL queries : as parameters - when collections are assigned as arguments ... that is passed to the query as a parameter. For example: 'English' IN :languages is TRUE if the argument ... are treated as synonyms. Criteria Query Collection Expressions JPQL collection operators and functions

). JPQL literals should be used sparingly as queries that use parameters instead of literals ... parameter values. Literals should only be embedded in JPQL queries when a single constant value ... '} Enum Literals JPA 2 adds support for enum literals. Enum literals in JPQL queries use

The following annotations are used to define static named JPA queries : The JPA Named Queries section of the ObjectDB Manual explains and demonstrates how to use these annotations to define named JPQL queries .

String values may appear in JPQL queries in various forms: as  string literals - e.g. 'abc ... expressions (which are more powerful than the LIKE operator). Criteria Query String Expressions JPQL string operators and functions (which are described above) are available also as JPA criteria query

Numeric values may appear in JPQL queries in many forms: as  numeric literals - e.g. 123 ... . Criteria Query Arithmetic Expressions JPQL arithmetic operators and functions (which are described above) are available also as JPA criteria query expressions. The CriteriaBuilder interface provides

The following interfaces are in use in representing general expressions in criteria queries : See the Query Expressions section for more details and examples.

The following JPA annotations are designated for SQL queries on relational databases: ObjectDB supports only the preferred JPA query language, JPQL, and silently ignores all the above annotations.

no-arg constructor. cannot be final and cannot have final methods or final instance variables . ObjectDB ... are forbidden). Instance (non static) variables cannot be final, but classes and methods can be final ... are represented in queries by entity names . By default, the entity name is the unqualified name

in the above sets extend the Bindable interface, which may be used in defining criteria query variables in the FROM clause: See the JPA Metamodel API page (in the ObjectDB manual) for more details and examples.

all the elements that can be used in a JDOQL query filter, except for parameters and variables ... ). The syntax of order expressions is similar to the syntax of query filters, except that variables ... . When a more selective retrieval is needed, JDOQL (JDO Query Language) is used. JDOQL for JDO is like

. Can you post the query ? Does it have a large number of variables ( 20) ? support Support Hi, Yes ... doesn't handle well queries with a lot of variables , and complex navigation (e.g.  $1.postalAddresses ... the limitation on the number of variables in a query . support Support

, derived attributes, grouping queries and aggregate queries ) which are usually missing from Object Oriented ... . Query program cache (for repeating queries with different arguments). Query result cache (for repeating queries with the same arguments). Many other internal caches. Indexing Single field and multi field

to view data in ObjectDB databases, execute JPQL and JDOQL queries and edit the content of databases ... and embeddable classes) in the database and their persistent fields and indexes. The [ Query ] window enables running JPQL and JDOQL queries , as discussed below. Closing a Database Connection Use the File Close

by ObjectDB to be a database URL rather than a persistence unit name. The $objectdb variable

hi, We've hit again against troubles with the variable naming when trying to get the query string ... us without ordering. The issue is that the name of the root variable is $1 as well as the name of our left join variable becomes $1. We're also adding a custom function expression in where clause

(which modify the database) have to be recorded. For debugging of query failure ... to accelerate the execution of relevant queries . The element The element specifies settings of the two cache mechanisms that ObjectDB manages for queries : The results attribute specifies the size

JDO Method in javax.jdo. Query void declareVariables (   String  variables ) Declare the unbound variables to be used in the query . Variables might be used in the filter, and these variables must be declared with their type. The unbound variable declaration is a String containing

the candidate collection of the query . Optional JDOQL components, such as filter, parameters, variables ... to browse databases, execute JDOQL queries , create new databases and edit the content of existing ... objects visually, navigate among them and execute queries is very valuable during development

variableDeclaration - the name of the variable in the outer query to bind the results ... . Parameters: sub - the subquery to add to this Query variableDeclaration - the name of the variable ... variableDeclaration - the name of the variable to be used in this Query candidateCollectionExpression - the candidate

on how to accomplish this. It is mainly a matter of style whether or not to use a separate variable ... content ( queries , object retrieval, reading) can be done without an active transaction. The default

variableDeclaration - the name of the variable in the outer query to bind the results ... JDO Method in javax.jdo. Query void addSubquery (    Query  sub,     ... ;   String... parameters ) Add a subquery to this query . A subquery is composed as a Query

to the candidate Class of the Query ; and for all variables there exists a value for which the filter ... JDO Method in javax.jdo. Query void setFilter (   String filter ) Set the filter for the query . The filter specification is a String containing a Boolean expression

JDO Method in javax.jdo. Query Object executeWithArray (   Object... parameters ) Execute the query and return the filtered Collection . The execution of the query obtains the values ... . The filter, import, declared parameters, declared variables , and ordering statements are verified

- the name of the variable to be used in this Query candidateCollectionExpression - the candidate ... JDO Method in javax.jdo. Query void addSubquery (    Query  sub,     ... ;   Map parameters ) Add a subquery to this query . The Map version of the method treats

JDO Method in javax.jdo. Query void declareImports (   String imports ) Set the import statements to be used to identify the fully qualified name of variables or parameters. Parameters and unbound variables might come from a different class from the candidate class, and the names

: sub - the subquery to add to this Query variableDeclaration - the name of the variable to be used ... JDO Method in javax.jdo. Query void addSubquery (    Query  sub,     ... ;   String parameter ) Add a subquery to this query . The String version of the method

a subquery to this query . Parameters: sub - the subquery to add to this Query variableDeclaration - the name of the variable in the outer query to bind the results of the subquery ... JDO Method in javax.jdo. Query void addSubquery (    Query  sub,    

are inherited except the name attribute. The $user variable (in the path attribute of $standard