Hi @DishaSharma ,
If we give notNull="false", it will not allow null values in that Particular column where as if we give notNull="true", it will allow null values in that particular column where we defined.
Generally we need to define all the Integer columns so that it wont allow NULL Values instead '0' should be populated , and for string Datatypes the Null values can be allowed.
Also for this use case:
<attribute desc="CSLS_SourceTimestamp" label="CSLS_SourceTimestamp" name="CSLS_SourceTimestamp"
notNull="false" sqlname="CSLS_SourceTimestamp" type="datetime"/>
It will not allow null values as for the attribute "CSLS_SourceTimestamp" the notNull="false" is defined.
You can test it by inserting a record without any value in Datetime field.
Also please refer to the below solved post
https://experienceleaguecommunities.adobe.com/t5/adobe-campaign-classic-questions/null-value-in-inte...
Regards,
Pravallika.