I need to bring from DB only one single result. How can I do that with JPA? I tried “select t from table t” but didn’t work. Any other ideas? Answer Try like this It should work UPDATE* You can also try like this
Tag: jpa
In which case do you use the JPA @JoinTable annotation?
In which case do you use the JPA @JoinTable annotation? Answer EDIT 2017-04-29: As pointed to by some of the commenters, the JoinTable example does not need the mappedBy annotation attribute. In fact, recent versions of Hibernate refuse to start up by printing the following error: Let’s pretend that you have an entity named Project and another entity named Task
autocomplete in vaadin?
I’m new to vaadin. How do I do autocomplete (actually, more like google suggest) on a huge set of data that cannot be loaded in memory, but instead performing a JPA query on every key event. Is it possible to capture key events on a textfield or combobox? Answer You could check out Henrik Paul’s SuperImmediateTextField, which is a Vaadin
Hibernate @ManyToOne references an unknown entity
I am receiving the following Hibernate Exception: @OneToOne or @ManyToOne on Matchup.awayTeam references an unknown entity: Team The simplified Matchup class looks like this: The simplified Team class looks like this: Notes: Both Matchup and Team have subclasses. I’m not sure if this impacts the situation. Both Matchup and Team are listed in my persistence.xml as being included. If I
How to specify SQL comments through JPA annotations?
Is there any way to specify SQL comments through JPA annotations? Comments for tables and columns. Answer Is there any way to specify SQL comments through JPA annotations? Comments for tables and columns. No. If you want to define tables and columns comments, your best option is to do it after the facts in the generated DDL, before executing it
Persisting set of Enums in a many-to-many unidirectional mapping
I’m using Hibernate 3.5.2-FINAL with annotations to specify my persistence mappings. I’m struggling with modelling a relationship between an Application and a set of Platforms. Each application is available for a set of platforms. From all the reading and searching I’ve done, I think I need to have the platform enum class be persisted as an Entity, and to have
Difference between FetchType LAZY and EAGER in Java Persistence API?
What is the difference between FetchType.LAZY and FetchType.EAGER in Java Persistence API? Answer Sometimes you have two entities and there’s a relationship between them. For example, you might have an entity called University and another entity called Student and a University might have many Students: The University entity might have some basic properties such as id, name, address, etc. as
How to set application name with JPA (EclipseLink)?
hello everybody i am using JPA with EclipseLink and oracle as DB and i need to set the property v$session of jdbc4 it allows to set an identification name to the application for auditing purposes but i had no lucky setting it up….i have been trying through entitiyManager following the example in this page: http://wiki.eclipse.org/Configuring_a_EclipseLink_JPA_Application_(ELUG) it does not show any
Is it possible to add JPA annotation to superclass instance variables?
I am creating entities that are the same for two different tables. In order do table mappings etc. different for the two entities but only have the rest of the code in one place – an abstract superclass. The best thing would be to be able to annotate generic stuff such as column names (since the will be identical) in
What is the “owning side” in an ORM mapping?
What exactly does the owning side mean? What is an explanation with some mapping examples (one to many, one to one, many to one)? The following text is an excerpt from the description of @OneToOne in Java EE 6 documentation. You can see the concept owning side in it. Defines a single-valued association to another entity that has one-to-one multiplicity.