About API

manual

JPA Criteria API Queries

Explains how to use the JPA Criteria API (CriteriaBuilder, CriteriaQuery, etc.) to build JPQL like queries. The JPA Criteria API provides an alternative way for defining JPA queries, which is mainly ... covers the following topics: JPA Criteria API vs JPQL First JPA Criteria Query Parameters in ... Query Expressions JPA Criteria API vs JPQL JPQL queries are defined as strings, similarly to SQL. JPA ...

 
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Which API should I use - JPA or JDO?

You can use ObjectDB with either the Java Persistence API (JPA) or the Java Data Objects (JDO) API. Both share similar architecture, design and abilities. When to prefer ...

 
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JPA Metamodel API

Explains how to use the JPA Metamodel API to retrieve details on the types and attributes of the persistent object model. The JPA Metamodel API provides the ability to examine the persistent object model and retrieve ... Interface The main interface of the JPA Metamodel API is Metamodel javax.persistence.metamodel.Metamodel JPA ... Hierarchy Types are represented in the Metamodel API by descendant interfaces of the Type ...

 
manual

JPA Query API

Describes the API that JPA provides for running queries against the database.... class to ObjectDB. Dynamic JPQL, Criteria API and Named Queries Building queries by passing JPQL query strings ... built dynamically at runtime. The JPA Criteria API provides an alternative way for building dynamic queries,  based on ...

 
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What is the Java Persistence API (JPA)?

The Java Persistence API (JPA) is a standard API for accessing databases from within Java applications. The main advantage of JPA over JDBC (the older Java API for interacting with databases) is that in JPA data is represented by ...

 
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JPA Query Structure (JPQL / Criteria)

Explains the structure of a JPQL query, which consists of 6 clauses: SELECT, FROM, WHERE, GROUP BY, HAVING, ORDER BY.... pages: SELECT clause (JPQL / Criteria API) FROM clause (JPQL / Criteria API) WHERE clause (JPQL / Criteria API) GROUP BY and HAVING ...

 
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SELECT clause (JPQL / Criteria API)

Explains how to use the SELECT clause and projections in a JPA/JPQL query.... SELECT in Criteria Queries The criteria query API  provides several ways for setting the SELECT clause. Single ... set SELECT content if any). Every valid criteria API expression can be used as selection, because all the criteria API ...

 
api-jpa

JPA Queries

Reference (JavaDoc) of all the JPA query types, including Query, TypedQuery, CriteriaBuilder, CriteriaQuery, Tuple, Root, Expression, Order, etc.... The JPA Query API section (in chapter 4 of the ObjectDB manual) provides detailed ... "SELECT c FROM Country" ). Criteria Query API Building dynamic queries whose structure is only known at runtime ... JPQL query. JPA 2 introduced the JPA Criteria Query API , as a cleaner alternative that enables building a dynamic query by using ...

 
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FROM clause (JPQL / Criteria API)

Explains how to use the FROM clause and JOIN expressions in a JPA/JPQL query. 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 a program, since both are used for iteration over o ...

 
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ORDER BY clause (JPQL / Criteria API)

Explains how to use the ORDER BY clause in a JPA/JPQL query.... DESC can be built using the criteria query API as follows: CriteriaQuery ...