LMS-835 bug in migration script and SamplePE fixed

SVN: 10613

openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/SamplePE.java

@@ -337,7 +337,6 @@ public class SamplePE implements IIdAndCodeHolder, Comparable<SamplePE>,
     }
 
     @ManyToOne(fetch = FetchType.LAZY)
-    @NotNull(message = ValidationMessages.EXPERIMENT_NOT_NULL_MESSAGE)
     @JoinColumn(name = ColumnNames.EXPERIMENT_COLUMN, updatable = true)
     @IndexedEmbedded(prefix = SearchFieldConstants.PREFIX_EXPERIMENT)
     private ExperimentPE getExperimentInternal()

openbis/source/sql/postgresql/migration/migration-031-032.sql

@@ -61,8 +61,6 @@ DROP SEQUENCE procedure_type_id_seq;
 --  Purpose:  Replace trigger SAMPLE_CODE_UNIQUENESS_CHECK 
 ------------------------------------------------------------------------------------
 
-DROP FUNCTION SAMPLE_CODE_UNIQUENESS_CHECK();
-
 CREATE OR REPLACE FUNCTION SAMPLE_CODE_UNIQUENESS_CHECK() RETURNS trigger AS $$
 DECLARE
    counter  INTEGER;