About SELECT

31-40 of 200Refresh
Issue
23

NullpointerException at a normal select

When I run the following code: EntityManager em = getEm(); Customer result = null; try {     logger.debug("Ident: "+ident);     result = em.createQuery("Select c from Customer c where c.identifier=:id", Customer.class).setParameter("id", ident).getSingleResult(); } catch (javax.persistence
Forum
23

Performance in SELECT statement

has around 30.000 rows) Example query looks like : String strSelect = "SELECT e FROM TestEntity
Forum
22

Class fields selection to store

Class fields selection to store
Forum
22

Selective merge/cascade of detatched entity

Selective merge/cascade of detatched entity
Manual
20

JPA Query Structure (JPQL / Criteria)

and easier to use in Java. JPQL Query Structure As with SQL, a JPQL SELECT query also consists of up to 6 clauses in the following format: SELECT ... FROM ... [WHERE ...] [GROUP BY ... [HAVING ...]] [ORDER BY ...] The first two clauses, SELECT and FROM are required in every retrieval query
Manual
19

Index Definition

execution. Indexes are especially efficient in lookup and range queries: SELECT p FROM Point p WHERE p.x = 100 SELECT p FROM Point p WHERE p.x BETWEEN 50 AND 80 SELECT p FROM Point p WHERE p.x >= 50 ... enables quick execution of the following queries: SELECT p FROM Point p WHERE p.x = 100 AND p.y = 100
Manual
18

JPA Criteria API Queries

JPA Criteria Query The following query string represents a minimal JPQL query: SELECT c FROM ... c = q.from(Country.class); q.select(c); The CriteriaBuilder interface serves as the main ... , the range variable, c, is also used in the SELECT clause as the query result expression
Tutorial
17

Java EE 6 JPA Tutorial - IntelliJ Project [2011-02-05]

IDEA: Select File > Open Project.... Select the guestbook-jee6 directory and click OK. Define the Server: Select File > Settings > Application Servers. Add Tomcat 6 Server if not set already (Tomcat has to be downloaded separately). Define Run Configuration: Select Run > Edit Configurations, click
Tutorial
17

Java EE 6 JPA Tutorial - IntelliJ Project

IDEA: Select File > Open Project.... Select the guestbook-jee6 directory and click OK. Define the Server: Select File > Settings > Application Servers. Add Tomcat 6 Server if not set already (Tomcat has to be downloaded separately). Define Run Configuration: Select Run > Edit Configurations, click
Tutorial
17

Spring MVC JPA Tutorial - IntelliJ Project [2011-02-06]

: Spring MVC JPA - Maven Project (7KB). Open the project in IntelliJ IDEA: Select File > Open Project.... Select the guestbook-spring directory and click OK. Define the Server: Select File > Settings ... ). Define Run Configuration: Select Run > Edit Configurations, click the + icon and select Tomcat