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JPA Criteria API Queries

The JPA Criteria API provides an alternative way for defining JPA queries, which is mainly useful for building dynamic queries whose exact structure is only known at runtime. JPA Criteria API vs JPQL ... of using the criteria API is that errors can be detected earlier, during compilation

SELECT clause (JPQL / Criteria API)

The criteria query API provides several ways for setting the SELECT clause. Single Selection Setting ... API expression can be used as selection, because all the criteria API expressions are represented by ... .name, c.capital.name FROM Country c can be defined using the criteria API as follows

WHERE clause (JPQL / Criteria API)

.population > :p can be built by using the criteria query API as follows: CriteriaQuery<Country> q = cb ... but they are especially dominant in the WHERE clause. WHERE in Criteria Queries The CriteriaQuery interface ... .area < :a can be built as a criteria query as follows: CriteriaQuery q = cb.createQuery(Country

Paths and Types in JPQL and Criteria API

one group, and COUNT calculates its size). Criteria Query Paths and Types Paths and navigations are represented in the JPA Criteria API by the Path interface and by its subinterfaces (From, Root, Join ... type method. For example, the following criteria expression checks if the type of a specified entity e

ORDER BY clause (JPQL / Criteria API)

Country c ORDER BY c.currency, c.population DESC can be built using the criteria query API as follows ... the result order would be undefined. ORDER BY in Criteria Queries The CriteriaQuery interface provides ... "))); Unlike other methods for setting criteria query clauses - the orderBy method takes a variable number

FROM clause (JPQL / Criteria API)

and aBs are all invalid variable names. FROM and JOIN in Criteria Queries FROM query identification variables are represented in criteria queries by sub interfaces of From: Range variables ... interfaces). Criteria Query Roots The CriteriaQuery's from method serves as a factory of Root instances

Comparison in JPQL and Criteria API

> :max Criteria Query Comparison JPQL comparison operators (which are described above) are available also as JPA criteria query expressions. The CriteriaBuilder interface provides factory methods ... of every one of these methods is a criteria expression. The second argument (and the third argument in between

Logical Operators in JPQL and Criteria API

Logical operators in JPQL and in JPA criteria queries enable composition of complex JPQL boolean ... part of its JDO support. Criteria Query Logical Operators Boolean Expressions and Predicates Boolean expressions are represented in criteria queries by Expression<Boolean> and descendant interfaces. For example

JPA Metamodel API

: The JPA Metamodel API may optionally be used with the JPA Criteria API. Many of the interfaces in ... The JPA Metamodel API, which is introduced in JPA 2.0, enables examining the classes, fields and properties of the persistent object model, similarly to the Java reflection API. The main interface


because it introduces the Country class to ObjectDB. Dynamic JPQL, Criteria API and Named Queries ... at runtime. The JPA Criteria API provides an alternative way for building dynamic queries, based

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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