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Revision as of 02:02, 18 April 2012 by (Talk | contribs)

Based on CDO 4.0-SR2

For some basic references to OCL please find or


We have the following, deliberately trivial, model:


We have the entities Patient and Konsultation (Consultation), which hold some generic attributes resp. features. The enumeration Geschlecht (sex) is self explaining. Each Konsultation belongsTo exactly one Patient, it is however not contained by the patient but exists as independent entity.


This section documents some queries based on the aforementioned model. It is work in progress.

Finding object references

The following OCL query finds all Konsultation entries in the entire repository, that belong to a certain Patient p, "injected" by the context. The element provided by the context is refered as self within the query.

CDOTransaction cdoTransaction = Activator.openSession("demo")
CDOQuery cqo = cdoTransaction.createQuery("ocl",
		((Patient)p).cdoID(), false);
List<Konsultation> lre = cqo.getResult(Konsultation.class);

The most important part in this query is the fact that we are comparing real objects, as k.belongsTo refers to an element of type Patient. For OCL CDO to evaluate this query correct, we need to pass the context objects CDOID object as otherwise we will receive an error. A direct comparison by simply passing (Patient)p as context is hence not possible.

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