JPA 2.0 Eclipse Link ... Composite primary keys

Posted by Parhs on Stack Overflow See other posts from Stack Overflow or by Parhs
Published on 2010-03-16T09:03:13Z Indexed on 2010/03/16 9:06 UTC
Read the original article Hit count: 203

Filed under:

composite

|

primary

|

jpa

|

2.0

I have two entities(actually more but it doenst matter)

Exam and Exam_Normals

Its a oneToMany relationship... The problem is that i need a primary key for Exams_Normals PK (Exam_ID Item) Item should be 1 2 3 4 5 etc.... But cant achieve it getting errors

An alternative would be to: I cound use an IDENTITY and a ManyToOne relationship at Exam_Normals but that should be like PK(Exam_Normals_ID) and a reference to Exam and an extra collumn Item to keep an order.. SO 3 collumns

But to avoid the alternative tried I tried with @IdClass and got errors Tried @EmbeddedID everything nothing works

Any idea??

© Stack Overflow or respective owner

Related posts about composite

Oracle ??????????? -2012?4??: Composite Patches

as seen on Oracle Blogs - Search for 'Oracle Blogs'
???????DBA?????????????bundle patches, ??Patch Set Updates(PSU)????????,??oracle??????bundle patches,??PSU,??,??????????????,???????????????????(one-off patch),????overlay patches,??????????????? Oracle?????????,???2012?4???Database PSU 11.2.0.3.2??,??????patch??Composite Patches… >>> More
Gone With the Wind?

as seen on Oracle Blogs - Search for 'Oracle Blogs'
Where Have All the Composites Gone? I was just asked to help out with an interesting problem at a customer. All their composites had disappeared from the EM console, none of them showed as loading in the log files and there was an ominous error message in the logs. Symptoms After a server… >>> More
NHibernate - mappping composite-id to table with non-composite primary key

as seen on Stack Overflow - Search for 'Stack Overflow'
I have table like this: ID - PK; KEY1 - UNIQUE1; KEY2 - UNIQUE1; If I don't want to use ID in my mappings, can I tell NHibernate to use KEY1 & KEY2 as a composite id? When I declare composite id like this: <composite-id> <key-property name="KEY1"/> <key-property name="KEY2"/> </composite-id> I… >>> More
SWT Layout for absolute positioning with minimal-spanning composites

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I'm writing a DND-editor where I can position elemtents (like buttons, images ...) freely via absolute positioning. Every element has a parent composite. These composites should span/grasp/embrace every element they contain. There can be two or more elements in the same composite and a composite… >>> More
Converting listview to a composite control

as seen on Stack Overflow - Search for 'Stack Overflow'
The link below shows a listview composite control in its most basic form however I can't seem to extend this to what I'm trying to do. http://stackoverflow.com/questions/92689/how-to-define-listview-templates-in-code My listview has 1 tablerow with 2 fields. The first field contains 1 element whilst… >>> More

Related posts about primary

How Can I Reference Multiple Primary Keys For A Vector Type Primary Key

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I have the following scenario: a table of projects and a table of persons, working on one or serveral projects. Also, I have a project id column (of type int), in the first table, which is a primary key there and I have a vector of project ids, as a column of type int, in my second table (persons)… >>> More
MySQL: Changing order of auto-incremented primary keys?

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I have a table with a auto-incremented primary key: user_id. For a currently theoretical reason, I might need to change a user_id to be something else than it was when originally created through auto-incrementation. This means there's a possibility that the keys will not be in incremental order… >>> More
Optimize MySQL query (ngrams, COUNT(), GROUP BY, ORDER BY)

as seen on Stack Overflow - Search for 'Stack Overflow'
I have a database with thousands of companies and their locations. I have implemented n-grams to optimize search. I am making one query to retrieve all the companies that match with the search query and another one to get a list with their locations and the number of companies in each location. The… >>> More
Ancillary Objects: Separate Debug ELF Files For Solaris

as seen on Oracle Blogs - Search for 'Oracle Blogs'
We introduced a new object ELF object type in Solaris 11 Update 1 called the Ancillary Object. This posting describes them, using material originally written during their development, the PSARC arc case, and the Solaris Linker and Libraries Manual. ELF objects contain allocable sections,… >>> More
Who could ask for more with LESS CSS? (Part 3 of 3–Clrizr)

as seen on Geeks with Blogs - Search for 'Geeks with Blogs'
Welcome back! In the first two posts in this series, I covered some of the awesome features in CSS precompilers such as SASS and LESS, as well as how to get an initial project setup up and running in ASP.Net MVC 4. In this post, I will cover an actual advanced example of using LESS in a project,… >>> More