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How to get a column with CDO [message #1852454]

Tue, 17 May 2022 04:49

I S

Messages: 13
Registered: May 2022

Junior Member

Hi all, I'm starting to learn CDO and I have a question.
I have a table my_table with multiple columns like:
- cdo_id
- other columns
- my_id

I have the following Java code

String finalSql = "SELECT cdo_id, id FROM my_table;
CDOQuery query = view.createQuery( "sql", finalSql );

Is it possible to retrieve 2 columns using CDOQuery and populate my result list List<ArrayList<Integer>> queryResultList? If not, how can I do it? In general, my question is how to get multiple columns from my table?

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Re: How to get a column with CDO [message #1852536 is a reply to message #1852454]

Sun, 22 May 2022 10:28

Eike Stepper

Messages: 6682
Registered: July 2009

Senior Member

You can add the following statement:

query.setParameter("mapQuery", true);

Each result is a Map with column names as kays and column values as values.

The test case org.eclipse.emf.cdo.tests.db.SQLQueryTest.testNonCDOObjectQueries_Complex_MAP() has an example, see https://git.eclipse.org/c/cdo/cdo.git/tree/plugins/org.eclipse.emf.cdo.tests.db/src/org/eclipse/emf/cdo/tests/db/SQLQueryTest.java#n374 .

Note that CDOIDs internally have long integer values, so your ArrayList<Integer> might not be able to store these values.

Cheers
/Eike

----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper

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