Questions Tagged With persistence

How to delete a dependent persistence object?

Nikel Weis — Thu, 18 Jun 2015 14:11:26 -0400

We have a persistence object A which has a property List(Object b).

When we remove one object b from the list with:

out.questionnaireConcept.QuestionnaireConceptParticpants.remove(in.participantToRemove);

and then try to persist this with:

ivy.persistence.***MuPersistence.merge(in.questionnaireConcept);

The participant which we tried to remove is still present in the database. I thought this could be set within the persistence definition in this window:

Do we have to remove the object b separately from the database or how can we achieve this?

How to work with NULL-Values in DateTime-Types using persistence?

Nikel Weis — Wed, 17 Jun 2015 11:45:23 -0400

We are facing the following problem: We are using the persistence-feature to handle complex objects. During the fetch we get values where a datetime-field is not set (NULL in the database) - when we try to write the entity object instance back to the database (merge) we get the following exception:

"SQLException: Only dates between January 1, 1753 and December 31, 9999 are accepted.
    DataException: could not update: [de.*****.qia.persistence.QuestionnaireQuestion#130]
    PersistenceException: org.hibernate.exception.DataException: could not update: [de.*****.qia.persistence.QuestionnaireQuestion#130]
    RollbackException: Error while committing the transaction
    Failed to excecute operation "merge" for persistence unit "qiaPersistence".

The reason is quite obvious - the auto-initialized value is out of the allowed range for the MSSQL-Server. But shouldn't NULL be the value to be written back?

How can we adress this? A workaround would be to enforce that a date is created during the initial persist but there could be situation where "NULL" is programmtically a valid entry.

How can we adress this issue?

Edit: RDBMS: MSSQL Express 2008

Which data-type can we use to save a file to a database using the IvyPersistence?

Nikel Weis — Tue, 26 May 2015 12:15:02 -0400

Currently we are trying to write a file to the database using Ivy's persistence API - which data-type can we use to achieve this or do we have to use a plain SQL-Step?

Persistence Object is not saved - ForeignKey is Null.

Nikel Weis — Tue, 29 Apr 2014 08:45:16 -0400

We have two persistence objects where a hasMany b. So a is a property of b.

Now we are creating an object of type b and asign the corresponding a-object to b.

b.a = a;

Then we try to save the newly created b object via:

ivy.persistence.persistenceUnit.merge(b);

Then it throws an error that the ForeignKey of a in table b cannot be null. But in the debugger object a is assigned correctly to object b.

In which pitfall did I run here?

Is it possible to create an ivy persistence object from String?

Nikel Weis — Fri, 25 Apr 2014 10:39:01 -0400

Usually a persistence object is created via:

import objects.Product;
// persist new created product
    Product product;
    product.name = "Product name";
    product.nr = 12;
    ivy.persistence.webshpo.persist(product);

What we are trying to do (for a dynamic interface) to dynamically create the persistence object with something like:

Object persistenceObject = Class.forName(in.persistenceClassName).newInstance();

Is that generally possible? Can that be achieved in a ScriptStep or just in a JavaClass?

Edit: We tried to give the full package name in the code mentioned above which returns a ClassNotFoundException:

Object persistenceObject = Class.forName("objects.Product").newInstance();

Edit 2: Changed persistenceUnit naming to persistenceObject according to Daniel's comment.

Is it possible to apply field order of a persistent data-class to database table?

Nikel Weis — Thu, 24 Apr 2014 10:29:21 -0400

I've noticed that if I use the persistence API to create a database table the order of the table columns is not the same as in the persistence data-class. Is it possible to keep the field order in a data-class to a database table?

Endless circular relation in 1:n relation correct?

Nikel Weis — Thu, 17 Apr 2014 08:43:07 -0400

I've a 1:n relation defined using the persistence api. One customer has n delivery adresses. In the history object this appears as customer object who has a list of delivery addresses. Those delivery addresses themself also have a customer attached and that customer a list of delivery addresses and so on and so forth. While this is semantically correct im wondering if I did something wrong or is this correct?