A small number of operator attributes can be declared to be either of ARRAY (multi-valued) type or non-array (single-valued) type. For example, the Update operator has an attribute called QueryBandSessInfo that can be declared either as
VARCHAR ARRAY QueryBandSessInfo,
Since only one form of this declaration can be in the $UPDATE template, the ARRAY form is the one declared in the template:
VARCHAR ARRAY QueryBandSessInfo = @UpdateQueryBandSessInfo
and if job variable QueryBandSessInfo has been assigned an array of values, there is agreement between type and number of values. If UpdateQueryBandSessInfo has been assigned a single value without array brackets, however, Teradata PT adds array brackets to the value, creating a one-element array to prevent a type mismatch between the attribute and its singular value.
All attributes that can have either an ARRAY or a scalar declaration are declared with the ARRAY form in their templates.