tdf#114596 dbaccess: fix mysterious dataloss bug (part 2)

Same problem as in 96ae2a33

Regression from 497e40ad

Change-Id: I00e7bf3559e688e7fbc5429ace2b5c18221c9890
Reviewed-on: https://gerrit.libreoffice.org/73146Reviewed-by: Michael Stahl <Michael.Stahl@cib.de>
Tested-by: Jenkins
(cherry picked from commit 58f121ef)
Reviewed-on: https://gerrit.libreoffice.org/73153

dbaccess/source/core/api/TableDeco.cxx

@@ -552,7 +552,7 @@ void ODBTableDecorator::refreshColumns()
         OContainerMediator* pMediator = new OContainerMediator( pCol, m_xColumnDefinitions );
         m_xColumnMediator = pMediator;
         pCol->setMediator( pMediator );
-        m_pColumns = pCol;
+        m_pColumns.reset(pCol);
     }
     else
         m_pColumns->reFill(aVector);

dbaccess/source/core/inc/TableDeco.hxx

@@ -71,10 +71,11 @@ namespace dbaccess
         css::uno::Reference< css::sdbc::XDatabaseMetaData >       m_xMetaData;
         css::uno::Reference< css::util::XNumberFormatsSupplier >  m_xNumberFormats;
 
-    // <properties>
+        // <properties>
         mutable sal_Int32                                         m_nPrivileges;
-    // </properties>
-        rtl::Reference<::connectivity::sdbcx::OCollection>       m_pColumns;
+        // </properties>
+        // note: this thing uses the ref-count of "this", see OCollection::acquire()!
+        std::unique_ptr<::connectivity::sdbcx::OCollection>       m_pColumns;
 
         // IColumnFactory
         virtual OColumn*    createColumn(const OUString& _rName) const override;