Questions Tagged With jpa

How can i persist a file as BLOB?

joha0123 — Thu, 26 May 2016 16:59:17 -0400

Hi,

i am using the primefaces fileupload widget, so users can upload attatchment files. right now, i save the files on the filesystem and i persist the path to the file in the database.

is there a way to save files as BLOB in relational database?

Thank you for your answers!

Avoid MultipleBagFetchException when referencing multiple collections of another type

joha0123 — Fri, 22 Apr 2016 22:04:56 -0400

I know how to store a single list in a JPA class. but now everytime i try to add another list to any other entity class i get an ivy:error:persistence, with following error message:

IvyScriptRuntimeException: IvyScript Runtime Exception in
    Instruction:
        ivy.persistence.axsosUnit.findAll(teamprojekt.Job.class)
    Block:
        teamprojekt.showDashboard.showDashboardData out;
        out = in;
        in.data.closedJobs = ivy.persistence.axsosUnit.findAll(teamprojekt.Job.class);

IvyScriptMethodInvocationException: Error calling method findAll(java.lang.Class) on an object of class ch.ivyteam.ivy.process.data.persistence.internal.IvyEntityManager.

PersistenceUnitException: Failed to excecute operation "findAll" for persistence unit "axsosUnit".

PersistenceUnitException: Could not create EntityManagerFactory of persistence unit'axsosUnit'

PersistenceException: [PersistenceUnit: axsosUnit] Unable to build EntityManagerFactory

MultipleBagFetchException: cannot simultaneously fetch multiple bags

I have read, that you cant use two lists in the same entity class, but i use them in different entity classes. maybe because they are nested?

the structure is: institutionList is inside education which is inside application which has the other list.

I have also read, the solution is to use a set instead of a list. can you explain how to do this? I've tried to change the list to a set from the entity class wizzard, but without success.

can you show me how to do this?

thank you very much

How can I add a List to a database

joha0123 — Wed, 20 Apr 2016 16:25:00 -0400

I am filling a List and then I try to write it to the database. We have two Entity Classes: Application and Education. The relationship is 1:N. (One application can have many educations)

In the Application entity class I have created a List of Education with the relationship ONE_TO_MANY. Mapped by attribute is appl. In the Education entity class i have created a field appl with the relationship MANY_TO_ONE.

The Problem is, that i have to initialize all objects before i can write data into them. this is impossible to do, because the application Object has a Education object in it and the Education Object has a Application object in it.

Is there an other way to save my data to a database?

thanks.