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77

JPA Query language support in OBjectDB / Sub query or nested Query

have given a sample typed query below which fails to work with ObjectDB and it runs very well with the Hibernate/MySQL JPA. We are using Spring Data here. It looks like a problem with Sub query or nested queries where I am using IN clause like below. @Query("SELECT product FROM Product product
21

GROUP BY and HAVING clauses

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
21

CRUD Database Operations with JPA

persisting objects in the database in more detail. JPA Queries with JPQL We can get the number of Point objects in the database by using a simple query: Query q1 = em.createQuery("SELECT COUNT(p) FROM Point p"); System.out.println("Total Points: " + q1.getSingleResult()); The query string ("SELECT
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Database Explorer

to view data in ObjectDB databases, execute JPQL and JDOQL queries and edit the content of databases ... 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 menu command
20

WHERE clause (JPQL / Criteria API)

JPQL query that retrieves selective objects from the database. Out of the four optional clauses of JPQL queries, the WHERE clause is definitely the most frequently used. How a WHERE Clause Works The following query retrieves only countries with a population size above a population size p: SELECT c
18

Index Definition

Querying without indexes requires iteration over entity objects in the database one by ... the iteration can be avoided and complex queries over millions of objects can be executed quickly ... ; : } Indexes in Queries ObjectDB manages a BTree for every index. A BTree is an ordered map data
17

Database Management Settings

" synchronized="false" />   <index-update enabled="true" priority="40" /> <query-cache results ... " operations (which modify the database) have to be recorded. For debugging of query failure ... to accelerate the execution of relevant queries. The <query-cache> element <query-cache results="32mb
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ORDER BY clause (JPQL / Criteria API)

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 ... from expressions in the SELECT clause are allowed in the ORDER BY clause. The following query
16

javax.persistence.TypedQuery

javax.persistence Interface TypedQuery<X> Superinterfaces: Query Interface used to control the execution of typed queries. Since: JPA 2.0 See Also: Query Parameter Learn how to define and use JPA/JPQL queries in Chapter 4 of the ObjectDB/JPA manual. int executeUpdate() Execute an update or delete
1

javax.jdo.JDOEntityManager

: IllegalArgumentException - if not an entity Since: JPA 1.0 Query createNamedQuery(String name) Create an instance of Query for executing a named query (in the Java Persistence query language or in native SQL). Create an instance of Query for executing a named query (in the Java Persistence query language or in

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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