#2 DataStage Solutions to Common Warnings/Error - Null Handling

Warnings/Errors Related to Null Handling -

1.1       When checking operator: When binding output interface field “XXXXX” to field “XXXXX”: Converting a nullable source to a non-nullable result

Cause: This can happen when reading from oracle database or in any processing stage where input column is defined as nullable and metadata in datastage is defined as non-nullable.

Resolution: Convert a nullable field to non  nullable. Need to apply available null functions in datastage or in the query.


1.2       APT_CombinedOperatorController(1),0: Field 'XXXXX' from input dataset '0' is NULL. Record dropped.

Cause: This can happen when there is no null handling mentioned on column and the same column is used in constraints/Stage Varibales.

Resolution:  Provide Null handling function to the column mentioned in constraint/Stage variable.

1.3       Fatal Error: Attempt to setIsNull() on the accessor interfacing to non-nullable field "XXXX".

Cause: This can happen when the column in source is nullable but in DB2 stage its mentioned as Non Nullable

Resolution: Change the Nullable field for the column to “Yes” instead of “No” i.e.


1.4       Exporting nullable field without null handling properties

Cause: This can happen when the columns are mentioned as nullable in sequential file stage and no representation for null values was specified.

Resolution: Specify Null field value in Format tab of sequential file stage.

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Lookup Stage behaviour

Today, I am gonna ask you a question, What value I will get from lookup when my datatype is integer (Not Null) and there is no match b/w source and reference data???

Generally, we say, NULL as there is no match b/w source and reference. But that's not true.
So let's see how the DataStage and Lookup behave :-)

When Source and Reference are NULLable -
-       If there is no match b/ source and reference, we will get NULL in output 

When Source and Reference are Not-NULLable -
-       If there is no match b/ source and reference, we will get DataStage Defaults for that datatype.
        such as - 0 for integer and empty string or '' for varchar when data is going out from lookup stage.

So, Be careful when you are planning to filter the data outside lookup stage based on referenced columns value as field in output file is not null, transformer stage don't receive a null (because it comes with the default value 0) and can't handle it as you expec.

Hoping, this will add one pointer in your learning. Let me know your thoughts in comment section.

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